CVE-2025-2817: firefox Path Traversal — Fix

Description

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 was fixed in Firefox 138, Firefox ESR 128.10, Firefox ESR 115.23, Thunderbird 138, and Thunderbird 128.10.

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CVSS v3.1 Score

8.8

HIGH

CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H

Weakness Type (CWE)

CWE-22 Path Traversal

Affected Products

Vendor	Product	Versions
mozilla	firefox	< 115.23.0
mozilla	firefox	< 138.0
mozilla	firefox	116.0 — 128.10.0
mozilla	thunderbird	< 128.10.0
mozilla	thunderbird	129.0 — 138.0

References

Advisories & Patches

https://www.mozilla.org/security/advisories/mfsa2025-28/ https://www.mozilla.org/security/advisories/mfsa2025-29/ https://www.mozilla.org/security/advisories/mfsa2025-30/ https://www.mozilla.org/security/advisories/mfsa2025-31/ https://www.mozilla.org/security/advisories/mfsa2025-32/

Other References

https://bugzilla.mozilla.org/show_bug.cgi?id=1917536 https://lists.debian.org/debian-lts-announce/2025/05/msg00022.html

Frequently Asked Questions

What is CVE-2025-2817? +

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 was fixed in Firefox 138, Firefox ESR 128.10, Firefox ESR 115.23, Thunderbird 138, and Thunderbird 128.10. It has a CVSS v3.1 base score of 8.8 (HIGH).

How severe is CVE-2025-2817? +

CVE-2025-2817 has a CVSS v3.1 score of 8.8 out of 10, rated HIGH. This is a high-severity vulnerability that should be prioritized for patching.

What products are affected by CVE-2025-2817? +

CVE-2025-2817 affects products from mozilla, specifically: firefox, thunderbird. Check the affected products table above for specific version ranges.

How do I check if I'm vulnerable to CVE-2025-2817? +

You can use Secably's free Website Scanner to check your website for known vulnerabilities. For infrastructure scanning, use the Port Scanner to identify exposed services that may be affected. Check the vendor advisories linked above for specific patch and version information.

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