cURL: Heap Overread via Secure Cookie Path Comparison Bug
CVE-2025-9086 Published on September 12, 2025

Out of bounds read for cookie path
1. A cookie is set using the `secure` keyword for `https://target` 2. curl is redirected to or otherwise made to speak with `http://target` (same hostname, but using clear text HTTP) using the same cookie set 3. The same cookie name is set - but with only a slash as path (`path="/"`). Since this site is not secure, the cookie *should* be ignored. 4. A bug in the path comparison logic makes curl read outside a heap buffer boundary The bug either causes a crash or it potentially makes the comparison come to the wrong conclusion and lets the clear-text site override the contents of the secure cookie, contrary to expectations and depending on the memory contents immediately following the single-byte allocation that holds the path. The presumed and correct behavior would be to plainly ignore the second set of the cookie since it was already set as secure on a secure host so overriding it on an insecure host should not be okay.

NVD

Vulnerability Analysis

CVE-2025-9086 is exploitable with network access, and does not require authorization privileges or user interaction. This vulnerability is considered to have a low attack complexity. The potential impact of an exploit of this vulnerability is considered to have no impact on confidentiality and integrity, and a high impact on availability.

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

Weakness Type

Out-of-bounds Read

The software reads data past the end, or before the beginning, of the intended buffer. Typically, this can allow attackers to read sensitive information from other memory locations or cause a crash. A crash can occur when the code reads a variable amount of data and assumes that a sentinel exists to stop the read operation, such as a NUL in a string. The expected sentinel might not be located in the out-of-bounds memory, causing excessive data to be read, leading to a segmentation fault or a buffer overflow. The software may modify an index or perform pointer arithmetic that references a memory location that is outside of the boundaries of the buffer. A subsequent read operation then produces undefined or unexpected results.


Products Associated with CVE-2025-9086

You can be notified by email with stack.watch whenever vulnerabilities like CVE-2025-9086 are published in these products:

Haxx Curl
 
Oracle
 
Apple iOS
 
Apple iPadOS
 
Apple macOS
 
Apple Macos Sonoma
 
Apple tvOS
 
Apple watchOS
 
Apple visionOS
 
Canonical Ubuntu Linux
 

Affected Versions

curl: curl: curl: Siemens RUGGEDCOM RST2428P: Siemens RUGGEDCOM RST2428P: Siemens SCALANCE XC-300/XR-300/XC-400/XR-500WG/XR-500 family: Siemens SCALANCE XCH328: Siemens SCALANCE XCM324: Siemens SCALANCE XCM328: Siemens SCALANCE XCM332: Siemens SCALANCE XRH334 (24 V DC, 8xFO, CC): Siemens SCALANCE XRM334 (230 V AC, 12xFO): Siemens SCALANCE XRM334 (230 V AC, 8xFO): Siemens SCALANCE XRM334 (230V AC, 2x10G, 24xSFP, 8xSFP+): Siemens SCALANCE XRM334 (24 V DC, 12xFO): Siemens SCALANCE XRM334 (24 V DC, 8xFO): Siemens SCALANCE XRM334 (24V DC, 2x10G, 24xSFP, 8xSFP+): Siemens SCALANCE XRM334 (2x230 V AC, 12xFO): Siemens SCALANCE XRM334 (2x230 V AC, 8xFO): Siemens SCALANCE XRM334 (2x230V AC, 2x10G, 24xSFP, 8xSFP+):

Exploit Probability

EPSS
1.40%
Percentile
71.28%

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.