CVE-2025-1938
MediumCVSS 6.5Exploitation Probability (EPSS)
Low risk25th percentile - higher than 25% of all known CVEs
Summary
Memory safety bugs present in Firefox 135, Thunderbird 135, Firefox ESR 128.7, and Thunderbird 128.7. Some showed evidence of memory corruption, potentially exploitable to run arbitrary code. Fixed in Firefox 136, Firefox ESR 128.8, Thunderbird 136, and Thunderbird 128.8.
Risk Assessment
Risk of arbitrary code execution in the browser or mail client, potentially leading to system compromise.
Recommendation
Update Firefox, Firefox ESR, and Thunderbird to the latest patched versions.
Other vulnerabilities in Firefox
See all- CVE-2026-106016Critical
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)
Memory safety bugs present in Firefox 135, Thunderbird 135, Firefox ESR 128.7, and Thunderbird 128.7. Some of these bugs showed evidence of memory corruption and we presume that with enough effort some of these could have been exploited to run arbitrary code. This vulnerability was fixed in Firefox 136, Firefox ESR 128.8, Thunderbird 136, and Thunderbird 128.8.
Vulnerability data from NVD (NIST) · CISA KEV · EPSS