CVE-2026-124900: Sandbox Escape Due to Use-after-free
Source GCVE Database
Not known to be exploited · CVSS 9.6 Critical.
Data as of 10 Nov 2026, 17:02 UTC
Thin evidence
One scorer or none| CISA-ADP | CVSS 3.1 | 9.6 |
|---|
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 10 Nov 2026
Detectable: no evidence on record.
No public nuclei template indexed
Weaponized: 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 10 Nov 2026.
What to do
AI-suggested
Users and administrators should update Firefox to version 160 or later, where this vulnerability is fixed. No additional mitigation steps are required as the vendor has provided an official fix. Applying the update promptly will eliminate the risk from this vulnerability.
Description
CVE-2026-124900 is a critical use-after-free vulnerability in the DOM Service Workers component of Firefox that allows sandbox escape. This flaw was fixed in Firefox version 160. 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.