CVE-2026-12329: Firefox ESR 140.12 Memory Safety Bug
CVE-2026-12329 Published on June 16, 2026
Memory safety bug fixed in Thunderbird ESR 140.12
Memory safety bug fixed in Thunderbird ESR 140.12. This vulnerability was fixed in Firefox ESR 140.12 and Thunderbird 140.12.
Vulnerability Analysis
CVE-2026-12329 can be exploited 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 small impact on availability.
Weakness Types
What is a Buffer Overflow Vulnerability?
The software performs operations on a memory buffer, but it can read from or write to a memory location that is outside of the intended boundary of the buffer.
CVE-2026-12329 has been classified to as a Buffer Overflow vulnerability or weakness.
What is a Dangling pointer Vulnerability?
Referencing memory after it has been freed can cause a program to crash, use unexpected values, or execute code.
CVE-2026-12329 has been classified to as a Dangling pointer vulnerability or weakness.
NULL Pointer Dereference
A NULL pointer dereference occurs when the application dereferences a pointer that it expects to be valid, but is NULL, typically causing a crash or exit. NULL pointer dereference issues can occur through a number of flaws, including race conditions, and simple programming omissions.
Products Associated with CVE-2026-12329
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Affected Versions
Mozilla Firefox:- Version 140.12, <= * is unaffected.
- Version 140.12, <= * is unaffected.
Exploit Probability
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.