CVE-2026-12329

Name: CVE-2026-12329
Creator: NVD / NIST
Published: 2026-06-16T13:16:33.657+00:00
License: https://creativecommons.org/publicdomain/zero/1.0/

MEDIUMCVSS 5.3/10EPSS 0.25%

Last modified Jun 17, 2026

CVE-2026-12329 is a medium-severity vulnerability rated 5.3/10 on the CVSS scale. Memory safety bug fixed in Thunderbird ESR 140.12. This vulnerability was fixed in Firefox ESR 140.12 and Thunderbird 140.12.. EPSS estimates a 0.25% chance of exploitation in the next 30 days.

Description

Memory safety bug fixed in Thunderbird ESR 140.12. This vulnerability was fixed in Firefox ESR 140.12 and Thunderbird 140.12.

Metrics

CVSS 3.1

5.3/10

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

EPSS Probability

0.25%

16.3th percentile

Probability of exploitation in the next 30 days. Learn more

Weakness Enumeration

Affected Software

Vendor	Product	Versions
Mozilla	Firefox	>= 140.0, < 140.12.0
Mozilla	Thunderbird	>= 140.0, < 140.12.0

References

https://bugzilla.mozilla.org/show_bug.cgi?id=2044738Permissions Required
https://www.mozilla.org/security/advisories/mfsa2026-58/Vendor Advisory
https://www.mozilla.org/security/advisories/mfsa2026-61/Vendor Advisory

Timeline

Published: Jun 16, 2026
Last Modified: Jun 17, 2026
Status: Analyzed

Frequently Asked Questions

What is CVE-2026-12329?

Memory safety bug fixed in Thunderbird ESR 140.12. This vulnerability was fixed in Firefox ESR 140.12 and Thunderbird 140.12.

How severe is CVE-2026-12329?

CVE-2026-12329 has a CVSS score of 5.3/10 (MEDIUM severity). The EPSS model estimates a 0.25% probability of exploitation in the next 30 days.

How do I fix CVE-2026-12329?

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-2026-12329?

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

Scan your code now

Source: NVD / NIST