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VulnerabilityPublished

CVE-2026-124864: Sandbox Escape Due to Use-after-free

Source GCVE Database

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Authoritative record:CVE-2026-124864· Critical 9.6

Not known to be exploited · CVSS 9.6 Critical.

Data as of 10 Nov 2026, 17:51 UTC

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

Thin evidence

One scorer or none
CVSS scores by source
CISA-ADPCVSS 3.19.6
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 10 Nov 2026

  2. Detectable: no evidence on record.

    No public nuclei template indexed

  3. Weaponized: 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 10 Nov 2026.

What to do

AI-suggested

A fix for this vulnerability is available. Users and administrators should update Firefox to version 160 or later, or Firefox ESR to version 115.45 or later, to remediate this issue. Applying these official patches fully mitigates the vulnerability. No additional mitigation actions are required beyond updating to the fixed versions.

Description

CVE-2026-124864 is a critical use-after-free vulnerability in the DOM Service Workers component of Firefox that allows sandbox escape. This flaw was addressed and fixed in Firefox 160 and Firefox ESR versions 115.45 and 153.7. The vulnerability has a high CVSS score of 9.6, indicating it can be exploited remotely without privileges and can lead to complete compromise of confidentiality, integrity, and availability. No known exploits in the wild have been reported. Users are advised to update to the fixed versions to mitigate the risk.

References

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