CVE-2026-109757 Affecting firefox-esr package, versions <153.5.0esr-1~deb12u1
Threat Intelligence
The probability is the direct output of the EPSS model, and conveys an overall sense of the threat of exploitation in the wild. The percentile measures the EPSS probability relative to all known EPSS scores. Note: This data is updated daily, relying on the latest available EPSS model version. Check out the EPSS documentation for more details.
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- published14 Oct 2026
- disclosed13 Oct 2026
Introduced: 13 Oct 2026
NewCVE-2026-109757 (opens in a new tab)How to fix?
Upgrade Echo:latest firefox-esr to version 153.5.0esr-1~deb12u1 or higher.
NVD Description
Note: Versions mentioned in the description apply only to the upstream firefox-esr package and not the firefox-esr package as distributed by Echo.
See How to fix? for Echo:latest relevant fixed versions and status.
Sandbox escape due to race condition in the Networking component. This vulnerability was fixed in Firefox 158, Firefox ESR 153.5, Thunderbird 158, and Thunderbird 153.5.
References
- https://advisory.echohq.com/cve/CVE-2026-109757
- https://bugzilla.mozilla.org/show_bug.cgi?id=2069910
- https://www.mozilla.org/security/advisories/mfsa2026-106/
- https://www.mozilla.org/security/advisories/mfsa2026-108/
- https://www.mozilla.org/security/advisories/mfsa2026-109/
- https://www.mozilla.org/security/advisories/mfsa2026-110/