CanvasWebGL Sandbox Escape in Firefox <147, ESR <140.7
CVE-2026-0878 Published on January 13, 2026
Sandbox escape due to incorrect boundary conditions in the Graphics: CanvasWebGL component
Sandbox escape due to incorrect boundary conditions in the Graphics: CanvasWebGL component. This vulnerability affects Firefox < 147, Firefox ESR < 140.7, Thunderbird < 147, and Thunderbird < 140.7.
Vulnerability Analysis
CVE-2026-0878 is exploitable with network access, requires user interaction. This vulnerability is consided to have a high level of attack complexity. The potential impact of an exploit of this vulnerability is considered to have a high impact on confidentiality and integrity, and no 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-2026-0878 has been classified to as a Buffer Overflow vulnerability or weakness.
Improper Input Validation
The product receives input or data, but it does not validate or incorrectly validates that the input has the properties that are required to process the data safely and correctly.
Products Associated with CVE-2026-0878
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Affected Versions
Mozilla Firefox:- Version unspecified and below 147 is affected.
- Version unspecified and below 140.7 is affected.
- Version unspecified and below 147 is affected.
- Version unspecified and below 140.7 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.