CVE-2026-117912: Mozilla Firefox · Same-origin policy bypass in the CSS Parsing and Computation component
Affects Mozilla FirefoxSource CVE Database V5
Not known to be exploited.
Data as of 27 Oct 2026, 15:31 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
A fix for this vulnerability is available and has been released in Firefox 159, Firefox ESR 115.44, and Firefox ESR 153.6. Users and administrators should update affected Firefox installations to these versions or later to mitigate the risk.
Description
CVE-2026-117912 is a same-origin policy bypass vulnerability in the CSS Parsing and Computation component of Mozilla Firefox. This security flaw allows bypassing the same-origin policy, which is a critical browser security mechanism. The vulnerability was fixed in Firefox version 159 and Firefox ESR versions 115.44 and 153.6.