Sandbox Escape in Mozilla Messaging System (Firefox/Thunderbird <147)
CVE-2026-0881 Published on January 13, 2026
Sandbox escape in the Messaging System component
Sandbox escape in the Messaging System component. This vulnerability affects Firefox < 147 and Thunderbird < 147.
Vulnerability Analysis
CVE-2026-0881 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 Types
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.
What is an Authorization Vulnerability?
The software does not restrict or incorrectly restricts access to a resource from an unauthorized actor.
CVE-2026-0881 has been classified to as an Authorization vulnerability or weakness.
Products Associated with CVE-2026-0881
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Affected Versions
Mozilla Firefox:- Version unspecified and below 147 is affected.
- Version unspecified and below 147 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.