XPath Parsing Vulnerability in Firefox and Thunderbird by Mozilla
CVE-2025-4087

6.5MEDIUM

Key Information:

Vendor

Mozilla
Status
Firefox
Firefox Esr
Thunderbird
Vendor
CVE Published:
29 April 2025

What is CVE-2025-4087?

A security issue exists in Firefox and Thunderbird where improper handling of XPath parsing can result in undefined behavior. This arises from missing null checks during attribute access, potentially leading to out-of-bounds read access. Such vulnerabilities can expose systems to memory corruption, affecting user data integrity and application stability. Affected versions include Firefox versions below 138 and Thunderbird versions below 138, along with their respective ESR versions.

Affected Version(s)

Firefox < 138

Firefox ESR < 128.10

Thunderbird < 138

References

https://bugzilla.mozilla.org/show_bug.cgi?id=1952465
https://www.mozilla.org/security/advisories/mfsa2025-28/
https://www.mozilla.org/security/advisories/mfsa2025-29/

CVSS V3.1

Score:
6.5
Severity:
MEDIUM
Confidentiality:
Low
Integrity:
Low
Availability:
Low
Attack Vector:
Network
Attack Complexity:
Low
Privileges Required:
None
User Interaction:
None
Scope:
Unchanged

Timeline

  • Vulnerability published

  • Vulnerability Reserved

Credit

Ivan Fratric
.
CVE-2025-4087 : XPath Parsing Vulnerability in Firefox and Thunderbird by Mozilla