Firefox sandbox escape via DOM boundary conditions <148
CVE-2026-2778 Published on February 24, 2026
Sandbox escape due to incorrect boundary conditions in the DOM: Core & HTML component
Sandbox escape due to incorrect boundary conditions in the DOM: Core & HTML component. This vulnerability was fixed in Firefox 148, Firefox ESR 115.33, Firefox ESR 140.8, Thunderbird 148, and Thunderbird 140.8.
Vulnerability Analysis
CVE-2026-2778 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-2026-2778 has been classified to as a Buffer Overflow vulnerability or weakness.
Products Associated with CVE-2026-2778
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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.