CVE-2026-109708: Sandbox escape due to incorrect boundary conditions in the Networking component
Source GCVE Database
Not known to be exploited · CVSS 9.6 Critical.
Data as of 27 Oct 2026, 17:12 UTC
- EPSS
- 0.3% chance of exploitation in 30 days – higher than 24% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.
CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:H/I:H/A:HExploitation evidence
Disclosed: evidence found.
CVE published 13 Oct 2026
Detectable: no evidence on record.
No public nuclei template indexed
Weaponised: no evidence on record.
No public exploit code indexed in Metasploit or Exploit-DB
Exploited in the wildExploited: no evidence on record.
Not in CISA KEV and no source reports exploitation
Observed by OffSeq MirageSeen by Mirage: no evidence on record.
No attack traffic recorded by OffSeq Mirage sensors
A missing step is not evidence of safety. Sources: cve.org (opens in a new tab), the Metasploit, Exploit-DB and nuclei-templates index as of 26 Oct 2026.
What to do
AI-suggested
This vulnerability has been fixed in Firefox 158 and Firefox ESR 153.5. Users and administrators should update affected Firefox installations to these versions or later to mitigate the risk. No additional action is required once the update is applied.
Description
CVE-2026-109708 is a critical vulnerability in Firefox's Networking component that allows sandbox escape due to incorrect boundary conditions. This flaw could enable an attacker to break out of the browser's sandbox environment, potentially leading to full system compromise. The issue was fixed in Firefox 158 and Firefox ESR 153.5.
References
- nvd.nist.gov/vuln/detail/CVE-2026-109708 (opens in a new tab)
- bugzilla.mozilla.org/show_bug.cgi?id=2059151 (opens in a new tab)
- mozilla.org/security/advisories/mfsa2026-106 (opens in a new tab)
- mozilla.org/security/advisories/mfsa2026-108 (opens in a new tab)
- mozilla.org/security/advisories/mfsa2026-109 (opens in a new tab)
- mozilla.org/security/advisories/mfsa2026-110 (opens in a new tab)
- mozilla.org/security/advisories/mfsa2026-119 (opens in a new tab)