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VulnerabilityPublished Updated

CVE-2026-109708: Sandbox escape due to incorrect boundary conditions in the Networking component

Source GCVE Database

0
Authoritative record:CVE-2026-109708· Critical 9.6

Not known to be exploited · CVSS 9.6 Critical.

Data as of 27 Oct 2026, 17:12 UTC

CVSS 3.1 base score
9.6Critical
How severe the flaw is on the 0–10 CVSS scale.
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:H

Exploitation evidence

  1. Disclosed: evidence found.

    CVE published 13 Oct 2026

  2. Detectable: no evidence on record.

    No public nuclei template indexed

  3. Weaponised: no evidence on record.

    No public exploit code indexed in Metasploit or Exploit-DB

  4. Exploited in the wild: no evidence on record.

    Not in CISA KEV and no source reports exploitation

  5. Observed by OffSeq 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

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