VulnerabilityDeferred
CVE-2026-109708
This vulnerability was fixed in Firefox 158, Firefox ESR 153.5, Thunderbird 158, Thunderbird 153.5, and Firefox ESR 115.44.
CRITICAL 9.6EPSS 0.32%
Does this matter?
High impact if exploited, but EPSS currently rates exploitation as unlikely (0.32%). Schedule it in the normal patch cycle and watch for a rise in EPSS or a public exploit.
Description
Sandbox escape due to incorrect boundary conditions in the Networking component. This vulnerability was fixed in Firefox 158, Firefox ESR 153.5, Thunderbird 158, Thunderbird 153.5, and Firefox ESR 115.44.
- CVSS 3.1
- 9.6 CRITICALCVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:H/I:H/A:H
- EPSS
- 0.32% probability · 25th percentile
- Public exploits
- None in Exploit-DB
- CISA KEV
- Not listed
- Weakness
- CWE-119
- Source
- security@mozilla.org
EPSS moved from 0.2% on 14 October 2026 to 0.3% on 26 October 2026.
References
- https://bugzilla.mozilla.org/show_bug.cgi?id=2059151
- 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/
- https://www.mozilla.org/security/advisories/mfsa2026-119/
Source: NVD record, EPSS from FIRST.org, KEV from CISA, exploits from Exploit-DB. Refreshed daily. Download this record as JSON.