CVE-2025-0237
MediumCVSS 5.4Exploitation Probability (EPSS)
Low risk47th percentile - higher than 47% of all known CVEs
Summary
The WebChannel API did not check the sending principal but accepted the principal being sent, which could lead to privilege escalation attacks. Fixed in Firefox 134, Firefox ESR 128.6, Thunderbird 134, and Thunderbird 128.6.
Risk Assessment
An attacker could exploit this to escalate privileges, potentially gaining control over the browser or email client.
Recommendation
Update Firefox or Thunderbird to the latest version that includes the fix.
Other vulnerabilities in Firefox
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Vulnerability in the DOM: Core & HTML component allows mitigation bypass. This issue was fixed in Firefox 158 and Thunderbird 158.
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Same-origin policy bypass in the DevTools component. Fixed in Firefox 158 and Thunderbird 158.
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Sandbox escape due to uninitialized memory in the DOM: Web Serial component. It was fixed in Firefox 158, Firefox ESR 153.5, Thunderbird 158, and Thunderbird 153.5.
- CVE-2026-109740Critical
Sandbox escape due to incorrect boundary conditions in the Widget: Win32 component. The flaw was fixed in Firefox 158, Firefox ESR 153.5, Thunderbird 158, and Thunderbird 153.5.
Original NVD description (English source)
The WebChannel API, which is used to transport various information across processes, did not check the sending principal but rather accepted the principal being sent. This could have led to privilege escalation attacks. This vulnerability was fixed in Firefox 134, Firefox ESR 128.6, Thunderbird 134, and Thunderbird 128.6.
Vulnerability data from NVD (NIST) · CISA KEV · EPSS