CVE-2026-8948
CriticalCVSS 9.1Exploitation Probability (EPSS)
Low risk34th percentile - higher than 34% of all known CVEs
Summary
A vulnerability in the Networking component of Firefox and Thunderbird allows bypassing the same-origin policy (SOP) in the DOM. The flaw was fixed in version 151 of both products.
Risk Assessment
An attacker could exploit this vulnerability to read or modify data from other origins, leading to theft of sensitive information such as session cookies or authentication tokens.
Recommendation
Immediately update Firefox and Thunderbird to version 151 or later. Ensure the updates are deployed on all workstations in the organization.
Other vulnerabilities in Firefox
See all- CVE-2026-106016Unknown
A vulnerability in the file handling component of the Firefox browser allows bypassing security mitigations. The issue was fixed in version 157.0.1.
- CVE-2026-100829Critical
Mitigation bypass in the DOM: Security component. This vulnerability was fixed in Firefox ESR 153.4, Thunderbird 157, Thunderbird 153.4, and Firefox 157.
- CVE-2026-100828Critical
Mitigation bypass in the Bookmarks & History component. This vulnerability was fixed in Firefox ESR 153.4, Thunderbird 157, Thunderbird 153.4, and Firefox 157.
- CVE-2026-100819Critical
Sandbox escape due to incorrect boundary conditions in the XPCOM component. Fixed in multiple Firefox and Thunderbird versions.
- CVE-2026-100818Critical
Sandbox escape due to use-after-free in the Widget: Gtk component. Fixed in multiple Firefox and Thunderbird versions.
- CVE-2026-100811Critical
Sandbox escape due to use-after-free in the DOM: Core & HTML component. Fixed in multiple Firefox and Thunderbird versions.
- CVE-2026-100810Critical
Other issue in the DevTools component. This vulnerability was fixed in Thunderbird 157 and Firefox 157.
- CVE-2026-100804Critical
Sandbox escape due to use-after-free in the Preferences: Backend component. Fixed in Thunderbird 157 and Firefox 157.
- CVE-2026-100800Critical
Sandbox escape due to use-after-free in the Disability Access APIs component. Fixed in Firefox ESR 153.4, Thunderbird 157, Thunderbird 153.4, and Firefox 157.
- CVE-2026-100794Critical
Vulnerability allows sandbox escape due to incorrect boundary conditions in the Internationalization component. It was fixed in Firefox ESR 153.4, Thunderbird 157, Thunderbird 140.17, Thunderbird 153.4, Firefox 157, and Firefox ESR 140.17.
Original NVD description (English source)
Same-origin policy bypass in the DOM: Networking component. This vulnerability was fixed in Firefox 151 and Thunderbird 151.
Vulnerability data from NVD (NIST) · CISA KEV · EPSS