Memory Corruption in Firefox/Thunderbird 151 Enables RCE
CVE-2026-12326 Published on June 16, 2026

Memory safety bugs fixed in Firefox 152 and Thunderbird 152
Memory safety bugs present in Firefox 151 and Thunderbird 151. 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 was fixed in Firefox 152 and Thunderbird 152.

NVD

Vulnerability Analysis

CVE-2026-12326 is exploitable with network access, requires user interaction. This vulnerability is consided to have a high level of attack complexity. The potential impact of an exploit of this vulnerability is considered to be very high.

Attack Vector:
NETWORK
Attack Complexity:
HIGH
Privileges Required:
NONE
User Interaction:
REQUIRED
Scope:
UNCHANGED
Confidentiality Impact:
HIGH
Integrity Impact:
HIGH
Availability Impact:
HIGH

Weakness Types

What is a Buffer Overflow Vulnerability?

The software performs operations on a memory buffer, but it can read from or write to a memory location that is outside of the intended boundary of the buffer.

CVE-2026-12326 has been classified to as a Buffer Overflow vulnerability or weakness.

What is a Dangling pointer Vulnerability?

The program dereferences a pointer that contains a location for memory that was previously valid, but is no longer valid. When a program releases memory, but it maintains a pointer to that memory, then the memory might be re-allocated at a later time. If the original pointer is accessed to read or write data, then this could cause the program to read or modify data that is in use by a different function or process. Depending on how the newly-allocated memory is used, this could lead to a denial of service, information exposure, or code execution.

CVE-2026-12326 has been classified to as a Dangling pointer vulnerability or weakness.


Products Associated with CVE-2026-12326

You can be notified by email with stack.watch whenever vulnerabilities like CVE-2026-12326 are published in these products:

Mozilla Firefox
 
Mozilla Thunderbird
 
Red Hat Enterprise Linux (RHEL)
 

Affected Versions

Mozilla Firefox: Mozilla Thunderbird: Red Hat Enterprise Linux 10: Red Hat Enterprise Linux 10: Red Hat Enterprise Linux 10: Red Hat Enterprise Linux 10: Red Hat Enterprise Linux 6: Red Hat Enterprise Linux 6: Red Hat Enterprise Linux 7: Red Hat Enterprise Linux 7: Red Hat Enterprise Linux 8: Red Hat Enterprise Linux 8: Red Hat Enterprise Linux 9: Red Hat Enterprise Linux 9:

Exploit Probability

EPSS
0.29%
Percentile
20.37%

EPSS (Exploit Prediction Scoring System) scores estimate the probability that a vulnerability will be exploited in the wild within the next 30 days. The percentile shows you how this score compares to all other vulnerabilities.