CVE-2025-4087

Name: CVE-2025-4087
Creator: NVD / NIST
Published: 2025-04-29T14:15:35.357+00:00
License: https://creativecommons.org/publicdomain/zero/1.0/

MEDIUMCVSS 4.8/10EPSS 0.26%

Last modified Jun 17, 2026

CVE-2025-4087 is a medium-severity vulnerability rated 4.8/10 on the CVSS scale. 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. EPSS estimates a 0.26% chance of exploitation in the next 30 days.

Description

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

Metrics

CVSS 3.1

4.8/10

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

EPSS Probability

0.26%

16.9th percentile

Probability of exploitation in the next 30 days. Learn more

Weakness Enumeration

CWE-125

Affected Software

Vendor	Product	Versions
Mozilla	Firefox	< 128.10
Mozilla	Firefox	< 138.0
Mozilla	Thunderbird	< 128.10.0
Mozilla	Thunderbird	< 138.0

References

https://bugzilla.mozilla.org/show_bug.cgi?id=1952465Permissions Required
https://www.mozilla.org/security/advisories/mfsa2025-28/Vendor Advisory
https://www.mozilla.org/security/advisories/mfsa2025-29/Vendor Advisory
https://www.mozilla.org/security/advisories/mfsa2025-31/Vendor Advisory
https://www.mozilla.org/security/advisories/mfsa2025-32/Vendor Advisory
https://lists.debian.org/debian-lts-announce/2025/05/msg00024.html

Timeline

Published: Apr 29, 2025
Last Modified: Jun 17, 2026
Status: Modified

Frequently Asked Questions

What is CVE-2025-4087?

How severe is CVE-2025-4087?

CVE-2025-4087 has a CVSS score of 4.8/10 (MEDIUM severity). The EPSS model estimates a 0.26% probability of exploitation in the next 30 days.

How do I fix CVE-2025-4087?

Check the vendor references and advisories linked above for patched versions and mitigation guidance. You can also run a Strix scan to test if your systems are affected.

Are you affected by CVE-2025-4087?

Run a free Strix scan to check your systems for this vulnerability.

Scan your code now

Source: NVD / NIST