Memory Safety Bug in Mozilla Firefox & Thunderbird <144 (CVE-2025-11721)
CVE-2025-11721 Published on October 14, 2025
Memory safety bug fixed in Firefox 144 and Thunderbird 144
Memory safety bug present in Firefox 143 and Thunderbird 143. This bug showed evidence of memory corruption and we presume that with enough effort this could have been exploited to run arbitrary code. This vulnerability affects Firefox < 144 and Thunderbird < 144.
Vulnerability Analysis
CVE-2025-11721 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 be critical as this vulnerability has a high impact to the confidentiality, integrity and availability of this component.
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-2025-11721 has been classified to as a Buffer Overflow vulnerability or weakness.
Products Associated with CVE-2025-11721
stack.watch emails you whenever new vulnerabilities are published in Mozilla Firefox or Mozilla Thunderbird. Just hit a watch button to start following.
Affected Versions
Mozilla Firefox:- Version unspecified and below 144 is affected.
- Version unspecified and below 144 is affected.
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.