DOM Mitigation Bypass in Firefox<147/ESR<115.32 & Thunderbird<147/ESR<140.7
CVE-2026-0877 Published on January 13, 2026
Mitigation bypass in the DOM: Security component
Mitigation bypass in the DOM: Security component. This vulnerability affects Firefox < 147, Firefox ESR < 115.32, Firefox ESR < 140.7, Thunderbird < 147, and Thunderbird < 140.7.
Vulnerability Analysis
CVE-2026-0877 can be exploited with network access, requires 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 high impact on confidentiality and integrity, and no impact on availability.
Weakness Type
Protection Mechanism Failure
The product does not use or incorrectly uses a protection mechanism that provides sufficient defense against directed attacks against the product. This weakness covers three distinct situations. A "missing" protection mechanism occurs when the application does not define any mechanism against a certain class of attack. An "insufficient" protection mechanism might provide some defenses - for example, against the most common attacks - but it does not protect against everything that is intended. Finally, an "ignored" mechanism occurs when a mechanism is available and in active use within the product, but the developer has not applied it in some code path.
Products Associated with CVE-2026-0877
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Affected Versions
Mozilla Firefox:- Version unspecified and below 147 is affected.
- Version unspecified and below 115.32 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.