Sandbox escape CVE-2026-2776 in Firefox <148 via Telemetry boundary
CVE-2026-2776 Published on February 24, 2026
Sandbox escape due to incorrect boundary conditions in the Telemetry component in External Software
Sandbox escape due to incorrect boundary conditions in the Telemetry component in External Software. This vulnerability was fixed in Firefox 148, Firefox ESR 115.33, Firefox ESR 140.8, Thunderbird 148, and Thunderbird 140.8.
Vulnerability Analysis
CVE-2026-2776 is exploitable 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-2026-2776 has been classified to as a Buffer Overflow vulnerability or weakness.
Products Associated with CVE-2026-2776
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Affected Versions
Mozilla Firefox:- Version 115.33, <= 115.* is unaffected.
- Version 140.8, <= 140.* is unaffected.
- Version 148, <= * is unaffected.
- Version 140.8, <= 140.* is unaffected.
- Version 148, <= * 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.