CVE-2026-12307: Memory safety bug in Firefox <152 (ESR 140.12) fixed
CVE-2026-12307 Published on June 16, 2026
Memory safety bug fixed in Firefox 152
Memory safety bug fixed in Firefox 152. This vulnerability was fixed in Firefox 152, Firefox ESR 140.12, Thunderbird 152, and Thunderbird 140.12.
Vulnerability Analysis
CVE-2026-12307 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 a small impact on confidentiality, a small impact on integrity and availability.
Weakness Type
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-2026-12307 has been classified to as a Buffer Overflow vulnerability or weakness.
Products Associated with CVE-2026-12307
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Affected Versions
Mozilla Firefox:- Version 140.12, <= 140.* is unaffected.
- Version 152, <= * is unaffected.
- Version 140.12, <= 140.* is unaffected.
- Version 152, <= * 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.