CVE-2026-117865: Mozilla Firefox · Use-after-free in the JavaScript: GC component
Affects Mozilla FirefoxSource CVE Database V5
Not known to be exploited.
Data as of 27 Oct 2026, 16:12 UTC
Rated High by Threat Radar's AI analysis · CVSS not yet scored by NVD
Exploitation evidence
Disclosed: evidence found.
CVE published 27 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
Users should update to Firefox 159 or later, or Firefox ESR 153.6 or later, to remediate this vulnerability. The vendor advisory confirms that the issue is fixed in these versions.
Description
CVE-2026-117865 is a use-after-free vulnerability in the JavaScript garbage collection (GC) component of Mozilla Firefox. This security flaw was addressed and fixed in Firefox version 159 and Firefox ESR 153.6. The vulnerability has been assigned a high impact rating by Mozilla. There are no known exploits in the wild at this time.