Mozilla Thunderbird Email client

Memory safety bugs present in Firefox 138, Thunderbird 138, Firefox ESR 128.10, and Thunderbird 128.10

CVE-2025-5268 - May 27, 2025

Memory safety bugs present in Firefox 138, Thunderbird 138, Firefox ESR 128.10, and Thunderbird 128.10. Some of these bugs showed evidence of memory corruption and we presume that with enough effort some of these could have been exploited to run arbitrary code. This vulnerability affects Firefox < 139, Firefox ESR < 128.11, Thunderbird < 139, and Thunderbird < 128.11.

Memory safety bug present in Firefox ESR 128.10, and Thunderbird 128.10

CVE-2025-5269 - May 27, 2025

Memory safety bug present in Firefox ESR 128.10, and Thunderbird 128.10. This bug showed evidence of memory corruption and we presume that with enough effort this could have been exploited to run arbitrary code. This vulnerability affects Firefox ESR < 128.11 and Thunderbird < 128.11.

Memory safety bugs present in Firefox 138 and Thunderbird 138

CVE-2025-5272 - May 27, 2025

Memory safety bugs present in Firefox 138 and Thunderbird 138. Some of these bugs showed evidence of memory corruption and we presume that with enough effort some of these could have been exploited to run arbitrary code. This vulnerability affects Firefox < 139 and Thunderbird < 139.

An attacker was able to perform an out-of-bounds read or write on a JavaScript `Promise` object

CVE-2025-4918 - May 17, 2025

An attacker was able to perform an out-of-bounds read or write on a JavaScript `Promise` object. This vulnerability affects Firefox < 138.0.4, Firefox ESR < 128.10.1, Firefox ESR < 115.23.1, Thunderbird < 128.10.2, and Thunderbird < 138.0.2.

An attacker was able to perform an out-of-bounds read or write on a JavaScript object by confusing array index sizes

CVE-2025-4919 - May 17, 2025

An attacker was able to perform an out-of-bounds read or write on a JavaScript object by confusing array index sizes. This vulnerability affects Firefox < 138.0.4, Firefox ESR < 128.10.1, Firefox ESR < 115.23.1, Thunderbird < 128.10.2, and Thunderbird < 138.0.2.

Thunderbird parses addresses in a way that can allow sender spoofing in case the server allows an invalid From address to be used

CVE-2025-3875 - May 14, 2025

Thunderbird parses addresses in a way that can allow sender spoofing in case the server allows an invalid From address to be used. For example, if the From header contains an (invalid) value "Spoofed Name ", Thunderbird treats spoofed@example.com as the actual address. This vulnerability affects Thunderbird < 128.10.1 and Thunderbird < 138.0.1.

Thunderbird's handling of the X-Mozilla-External-Attachment-URL header can be exploited to execute JavaScript in the file:/// context

CVE-2025-3909 - May 14, 2025

Thunderbird's handling of the X-Mozilla-External-Attachment-URL header can be exploited to execute JavaScript in the file:/// context. By crafting a nested email attachment (message/rfc822) and setting its content type to application/pdf, Thunderbird may incorrectly render it as HTML when opened, allowing the embedded JavaScript to run without requiring a file download. This behavior relies on Thunderbird auto-saving the attachment to /tmp and linking to it via the file:/// protocol, potentially enabling JavaScript execution as part of the HTML. This vulnerability affects Thunderbird < 128.10.1 and Thunderbird < 138.0.1.

It was possible to craft an email that showed a tracking link as an attachment

CVE-2025-3932 - May 14, 2025

It was possible to craft an email that showed a tracking link as an attachment. If the user attempted to open the attachment, Thunderbird automatically accessed the link. The configuration to block remote content did not prevent that. Thunderbird has been fixed to no longer allow access to web pages listed in the X-Mozilla-External-Attachment-URL header of an email. This vulnerability affects Thunderbird < 128.10.1 and Thunderbird < 138.0.1.

Thunderbird's update mechanism

CVE-2025-2817 - April 29, 2025

Thunderbird's update mechanism allowed a medium-integrity user process to interfere with the SYSTEM-level updater by manipulating the file-locking behavior. By injecting code into the user-privileged process, an attacker could bypass intended access controls, allowing SYSTEM-level file operations on paths controlled by a non-privileged user and enabling privilege escalation. This vulnerability affects Firefox < 138, Firefox ESR < 128.10, Firefox ESR < 115.23, Thunderbird < 138, and Thunderbird < 128.10.

Modification of specific WebGL shader attributes could trigger an out-of-bounds read

CVE-2025-4082 - April 29, 2025

Modification of specific WebGL shader attributes could trigger an out-of-bounds read, which, when chained with other vulnerabilities, could be used to escalate privileges. *This bug only affects Thunderbird for macOS. Other versions of Thunderbird are unaffected.* This vulnerability affects Firefox < 138, Firefox ESR < 128.10, Firefox ESR < 115.23, Thunderbird < 138, and Thunderbird < 128.10.

A process isolation vulnerability in Thunderbird stemmed from improper handling of javascript: URIs, which could

CVE-2025-4083 - April 29, 2025

A process isolation vulnerability in Thunderbird stemmed from improper handling of javascript: URIs, which could allow content to execute in the top-level document's process instead of the intended frame, potentially enabling a sandbox escape. This vulnerability affects Firefox < 138, Firefox ESR < 128.10, Firefox ESR < 115.23, Thunderbird < 138, and Thunderbird < 128.10.

Due to insufficient escaping of the special characters in the "copy as cURL" feature

CVE-2025-4084 - April 29, 2025

Due to insufficient escaping of the special characters in the "copy as cURL" feature, an attacker could trick a user into using this command, potentially leading to local code execution on the user's system. *This bug only affects Firefox for Windows. Other versions of Firefox are unaffected.* This vulnerability affects Firefox ESR < 128.10, Firefox ESR < 115.23, and Thunderbird < 128.10.

An attacker with control over a content process could potentially leverage the privileged UITour actor to leak sensitive information or escalate privileges

CVE-2025-4085 - April 29, 2025

An attacker with control over a content process could potentially leverage the privileged UITour actor to leak sensitive information or escalate privileges. This vulnerability affects Firefox < 138 and Thunderbird < 138.

A specially crafted filename containing a large number of encoded newline characters could obscure the file's extension when displayed in the download dialog

CVE-2025-4086 - April 29, 2025

A specially crafted filename containing a large number of encoded newline characters could obscure the file's extension when displayed in the download dialog. *This bug only affects Thunderbird for Android. Other versions of Thunderbird are unaffected.* This vulnerability affects Firefox < 138 and Thunderbird < 138.

A vulnerability was identified in Thunderbird where XPath parsing could trigger undefined behavior due to missing null checks during attribute access

CVE-2025-4087 - April 29, 2025

A vulnerability was identified in Thunderbird where XPath parsing could trigger undefined behavior due to missing null checks during attribute access. This could lead to out-of-bounds read access and potentially, memory corruption. This vulnerability affects Firefox < 138, Firefox ESR < 128.10, Thunderbird < 138, and Thunderbird < 128.10.

A security vulnerability in Thunderbird allowed malicious sites to use redirects to send credentialed requests to arbitrary endpoints on any site

CVE-2025-4088 - April 29, 2025

A security vulnerability in Thunderbird allowed malicious sites to use redirects to send credentialed requests to arbitrary endpoints on any site that had invoked the Storage Access API. This enabled potential Cross-Site Request Forgery attacks across origins. This vulnerability affects Firefox < 138 and Thunderbird < 138.

Due to insufficient escaping of special characters in the "copy as cURL" feature

CVE-2025-4089 - April 29, 2025

Due to insufficient escaping of special characters in the "copy as cURL" feature, an attacker could trick a user into using this command, potentially leading to local code execution on the user's system. This vulnerability affects Firefox < 138 and Thunderbird < 138.

A vulnerability existed in Thunderbird for Android where potentially sensitive library locations were logged via Logcat

CVE-2025-4090 - April 29, 2025

A vulnerability existed in Thunderbird for Android where potentially sensitive library locations were logged via Logcat. This vulnerability affects Firefox < 138 and Thunderbird < 138.

Memory safety bugs present in Firefox 137, Thunderbird 137, Firefox ESR 128.9, and Thunderbird 128.9

CVE-2025-4091 - April 29, 2025

Memory safety bugs present in Firefox 137, Thunderbird 137, Firefox ESR 128.9, and Thunderbird 128.9. Some of these bugs showed evidence of memory corruption and we presume that with enough effort some of these could have been exploited to run arbitrary code. This vulnerability affects Firefox < 138, Firefox ESR < 128.10, Thunderbird < 138, and Thunderbird < 128.10.

Memory safety bugs present in Firefox 137 and Thunderbird 137

CVE-2025-4092 - April 29, 2025

Memory safety bugs present in Firefox 137 and Thunderbird 137. Some of these bugs showed evidence of memory corruption and we presume that with enough effort some of these could have been exploited to run arbitrary code. This vulnerability affects Firefox < 138 and Thunderbird < 138.

Memory safety bug present in Firefox ESR 128.9, and Thunderbird 128.9

CVE-2025-4093 - April 29, 2025

Memory safety bug present in Firefox ESR 128.9, and Thunderbird 128.9. This bug showed evidence of memory corruption and we presume that with enough effort this could have been exploited to run arbitrary code. This vulnerability affects Firefox ESR < 128.10 and Thunderbird < 128.10.

By crafting a malformed file name for an attachment in a multipart message, an attacker

CVE-2025-2830 - April 15, 2025

By crafting a malformed file name for an attachment in a multipart message, an attacker can trick Thunderbird into including a directory listing of /tmp when the message is forwarded or edited as a new message. This vulnerability could allow attackers to disclose sensitive information from the victim's system. This vulnerability is not limited to Linux; similar behavior has been observed on Windows as well. This vulnerability affects Thunderbird < 137.0.2 and Thunderbird < 128.9.2.

Thunderbird processes the X-Mozilla-External-Attachment-URL header to handle attachments which can be hosted externally

CVE-2025-3522 - April 15, 2025

Thunderbird processes the X-Mozilla-External-Attachment-URL header to handle attachments which can be hosted externally. When an email is opened, Thunderbird accesses the specified URL to determine file size, and navigates to it when the user clicks the attachment. Because the URL is not validated or sanitized, it can reference internal resources like chrome:// or SMB share file:// links, potentially leading to hashed Windows credential leakage and opening the door to more serious security issues. This vulnerability affects Thunderbird < 137.0.2 and Thunderbird < 128.9.2.

When an email contains multiple attachments with external links

CVE-2025-3523 - April 15, 2025

When an email contains multiple attachments with external links via the X-Mozilla-External-Attachment-URL header, only the last link is shown when hovering over any attachment. Although the correct link is used on click, the misleading hover text could trick users into downloading content from untrusted sources. This vulnerability affects Thunderbird < 137.0.2 and Thunderbird < 128.9.2.

Memory safety bugs present in Firefox 136 and Thunderbird 136

CVE-2025-3034 - April 01, 2025

Memory safety bugs present in Firefox 136 and Thunderbird 136. Some of these bugs showed evidence of memory corruption and we presume that with enough effort some of these could have been exploited to run arbitrary code. This vulnerability affects Firefox < 137 and Thunderbird < 137.

Memory Corruption

After selecting a malicious Windows `.url` shortcut from the local filesystem, an unexpected file could be uploaded

CVE-2025-3033 - April 01, 2025

After selecting a malicious Windows `.url` shortcut from the local filesystem, an unexpected file could be uploaded. *This bug only affects Firefox on Windows. Other operating systems are unaffected.* This vulnerability affects Firefox < 137 and Thunderbird < 137.

Leaking of file descriptors from the fork server to web content processes could allow for privilege escalation attacks

CVE-2025-3032 - April 01, 2025

Leaking of file descriptors from the fork server to web content processes could allow for privilege escalation attacks. This vulnerability affects Firefox < 137 and Thunderbird < 137.

An attacker could read 32 bits of values spilled onto the stack in a JIT compiled function

CVE-2025-3031 - April 01, 2025

An attacker could read 32 bits of values spilled onto the stack in a JIT compiled function. This vulnerability affects Firefox < 137 and Thunderbird < 137.

Memory safety bugs present in Firefox 136, Thunderbird 136, Firefox ESR 128.8, and Thunderbird 128.8

CVE-2025-3030 - April 01, 2025

Memory safety bugs present in Firefox 136, Thunderbird 136, Firefox ESR 128.8, and Thunderbird 128.8. Some of these bugs showed evidence of memory corruption and we presume that with enough effort some of these could have been exploited to run arbitrary code. This vulnerability affects Firefox < 137, Firefox ESR < 128.9, Thunderbird < 137, and Thunderbird < 128.9.

A crafted URL containing specific Unicode characters could have hidden the true origin of the page

CVE-2025-3029 - April 01, 2025

A crafted URL containing specific Unicode characters could have hidden the true origin of the page, resulting in a potential spoofing attack. This vulnerability affects Firefox < 137, Firefox ESR < 128.9, Thunderbird < 137, and Thunderbird < 128.9.

JavaScript code running while transforming a document with the XSLTProcessor could lead to a use-after-free

CVE-2025-3028 - April 01, 2025

JavaScript code running while transforming a document with the XSLTProcessor could lead to a use-after-free. This vulnerability affects Firefox < 137, Firefox ESR < 115.22, Firefox ESR < 128.9, Thunderbird < 137, and Thunderbird < 128.9.

When requesting an OpenPGP key

CVE-2025-26695 - March 10, 2025

When requesting an OpenPGP key from a WKD server, an incorrect padding size was used and a network observer could have learned the length of the requested email address. This vulnerability affects Thunderbird < 136 and Thunderbird < 128.8.

Certain crafted MIME email messages

CVE-2025-26696 - March 10, 2025

Certain crafted MIME email messages that claimed to contain an encrypted OpenPGP message, which instead contained an OpenPGP signed message, were wrongly shown as being encrypted. This vulnerability affects Thunderbird < 136 and Thunderbird < 128.8.

On Windows, a compromised content process could use bad StreamData sent over AudioIPC to trigger a use-after-free in the Browser process

CVE-2025-1930 - March 04, 2025

On Windows, a compromised content process could use bad StreamData sent over AudioIPC to trigger a use-after-free in the Browser process. This could have led to a sandbox escape. This vulnerability affects Firefox < 136, Firefox ESR < 115.21, Firefox ESR < 128.8, Thunderbird < 136, and Thunderbird < 128.8.

When String.toUpperCase() caused a string to get longer it was possible for uninitialized memory to be incorporated into the result string This vulnerability affects Firefox < 136 and Thunderbird < 136.

CVE-2025-1942 - March 04, 2025

When String.toUpperCase() caused a string to get longer it was possible for uninitialized memory to be incorporated into the result string This vulnerability affects Firefox < 136 and Thunderbird < 136.

An inconsistent comparator in xslt/txNodeSorter could have resulted in potentially exploitable out-of-bounds access

CVE-2025-1932 - March 04, 2025

An inconsistent comparator in xslt/txNodeSorter could have resulted in potentially exploitable out-of-bounds access. Only affected version 122 and later. This vulnerability affects Firefox < 136, Firefox ESR < 128.8, Thunderbird < 136, and Thunderbird < 128.8.

Memory safety bugs present in Firefox 135, Thunderbird 135, Firefox ESR 128.7, and Thunderbird 128.7

CVE-2025-1938 - March 04, 2025

Memory safety bugs present in Firefox 135, Thunderbird 135, Firefox ESR 128.7, and Thunderbird 128.7. Some of these bugs showed evidence of memory corruption and we presume that with enough effort some of these could have been exploited to run arbitrary code. This vulnerability affects Firefox < 136, Firefox ESR < 128.8, Thunderbird < 136, and Thunderbird < 128.8.

It was possible to cause a use-after-free in the content process side of a WebTransport connection

CVE-2025-1931 - March 04, 2025

It was possible to cause a use-after-free in the content process side of a WebTransport connection, leading to a potentially exploitable crash. This vulnerability affects Firefox < 136, Firefox ESR < 115.21, Firefox ESR < 128.8, Thunderbird < 136, and Thunderbird < 128.8.

On 64-bit CPUs, when the JIT compiles WASM i32 return values they can pick up bits from left over memory

CVE-2025-1933 - March 04, 2025

On 64-bit CPUs, when the JIT compiles WASM i32 return values they can pick up bits from left over memory. This can potentially cause them to be treated as a different type. This vulnerability affects Firefox < 136, Firefox ESR < 115.21, Firefox ESR < 128.8, Thunderbird < 136, and Thunderbird < 128.8.

It was possible to interrupt the processing of a RegExp bailout and run additional JavaScript

CVE-2025-1934 - March 04, 2025

It was possible to interrupt the processing of a RegExp bailout and run additional JavaScript, potentially triggering garbage collection when the engine was not expecting it. This vulnerability affects Firefox < 136, Firefox ESR < 128.8, Thunderbird < 136, and Thunderbird < 128.8.

Memory safety bugs present in Firefox 135, Thunderbird 135, Firefox ESR 115.20, Firefox ESR 128.7, and Thunderbird 128.7

CVE-2025-1937 - March 04, 2025

Memory safety bugs present in Firefox 135, Thunderbird 135, Firefox ESR 115.20, Firefox ESR 128.7, and Thunderbird 128.7. Some of these bugs showed evidence of memory corruption and we presume that with enough effort some of these could have been exploited to run arbitrary code. This vulnerability affects Firefox < 136, Firefox ESR < 115.21, Firefox ESR < 128.8, Thunderbird < 136, and Thunderbird < 128.8.

jar: URLs retrieve local file content packaged in a ZIP archive

CVE-2025-1936 - March 04, 2025

jar: URLs retrieve local file content packaged in a ZIP archive. The null and everything after it was ignored when retrieving the content from the archive, but the fake extension after the null was used to determine the type of content. This could have been used to hide code in a web extension disguised as something else like an image. This vulnerability affects Firefox < 136, Firefox ESR < 128.8, Thunderbird < 136, and Thunderbird < 128.8.

Memory safety bugs present in Firefox 135 and Thunderbird 135

CVE-2025-1943 - March 04, 2025

Memory safety bugs present in Firefox 135 and Thunderbird 135. Some of these bugs showed evidence of memory corruption and we presume that with enough effort some of these could have been exploited to run arbitrary code. This vulnerability affects Firefox < 136 and Thunderbird < 136.

A web page could trick a user into setting that site as the default handler for a custom URL protocol

CVE-2025-1935 - March 04, 2025

A web page could trick a user into setting that site as the default handler for a custom URL protocol. This vulnerability affects Firefox < 136, Firefox ESR < 128.8, Thunderbird < 136, and Thunderbird < 128.8.

A race during concurrent delazification could have led to a use-after-free

CVE-2025-1012 7.5 - High - February 04, 2025

A race during concurrent delazification could have led to a use-after-free. This vulnerability affects Firefox < 135, Firefox ESR < 115.20, Firefox ESR < 128.7, Thunderbird < 128.7, and Thunderbird < 135.

Dangling pointer

A bug in WebAssembly code generation could have lead to a crash

CVE-2025-1011 8.8 - High - February 04, 2025

A bug in WebAssembly code generation could have lead to a crash. It may have been possible for an attacker to leverage this to achieve code execution. This vulnerability affects Firefox < 135, Firefox ESR < 128.7, Thunderbird < 128.7, and Thunderbird < 135.

An attacker could have caused a use-after-free via the Custom Highlight API, leading to a potentially exploitable crash

CVE-2025-1010 8.8 - High - February 04, 2025

An attacker could have caused a use-after-free via the Custom Highlight API, leading to a potentially exploitable crash. This vulnerability affects Firefox < 135, Firefox ESR < 115.20, Firefox ESR < 128.7, Thunderbird < 128.7, and Thunderbird < 135.

Dangling pointer

An attacker could have caused a use-after-free via crafted XSLT data, leading to a potentially exploitable crash

CVE-2025-1009 9.8 - Critical - February 04, 2025

An attacker could have caused a use-after-free via crafted XSLT data, leading to a potentially exploitable crash. This vulnerability affects Firefox < 135, Firefox ESR < 115.20, Firefox ESR < 128.7, Thunderbird < 128.7, and Thunderbird < 135.

Dangling pointer

Thunderbird displayed an incorrect sender address if the From field of an email used the invalid group name syntax

CVE-2025-0510 6.5 - Medium - February 04, 2025

Thunderbird displayed an incorrect sender address if the From field of an email used the invalid group name syntax that is described in CVE-2024-49040. This vulnerability affects Thunderbird < 128.7 and Thunderbird < 135.

Memory safety bugs present in Firefox 134 and Thunderbird 134

CVE-2025-1020 9.8 - Critical - February 04, 2025

Memory safety bugs present in Firefox 134 and Thunderbird 134. Some of these bugs showed evidence of memory corruption and we presume that with enough effort some of these could have been exploited to run arbitrary code. This vulnerability affects Firefox < 135 and Thunderbird < 135.

Memory Corruption