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CVE-2025-14321VulnerabilityPublished Updated

Red Hat Security Advisory: firefox security update

Affects Red Hat firefoxSource GCVE Database

0

Mentioned vulnerabilities

Authoritative record:CVE-2025-14321· Critical 9.8

Not known to be exploited · CVSS 9.8 Critical · fixed in Red Hat package updates : patch Red Hat firefox as a priority.

Data as of 26 Oct 2026, 10:12 UTC

CVSS 3.1 base score
9.8Critical
How severe the flaw is on the 0–10 CVSS scale.
EPSS
0.5% chance of exploitation in 30 days – higher than 48% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.
Patch
Available – fixed in 140.6.0
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

Exploitation evidence

  1. Disclosed: evidence found.

    CVE published 9 Dec 2025

  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

Affected software

ProductAffectedFixed in
Red Hatredhat/firefoxpkg:rpm/redhat/firefoxOther threatsAffected
  • =10.0
Fixed in–
Red Hatredhat/thunderbirdpkg:rpm/redhat/thunderbirdOther threatsAffected
  • =10.0
Fixed in–

Check your own hosts for these packages with threat-finder (opens in a new tab), our free open-source scanner.

AI-suggested

Red Hat has released updated packages for Mozilla Thunderbird ESR 140.6.0 and Firefox ESR 140.6 as part of Red Hat Enterprise Linux 10.0 Extended Update Support. Users should apply these official updates promptly to remediate the vulnerabilities. For detailed update instructions, refer to the Red Hat advisory at https://access.redhat.com/articles/11258. No additional mitigation steps are indicated by the vendor.

Description

Multiple security vulnerabilities have been identified and fixed in Mozilla Thunderbird ESR 140.6.0 and Firefox ESR 140.6, including use-after-free, sandbox escape, privilege escalation, JIT miscompilation, same-origin policy bypass, and memory safety bugs. These issues affect components such as WebRTC signaling, Graphics CanvasWebGL, DOM Notifications, JavaScript Engine JIT, Netmonitor, and Request Handling. The update addresses these vulnerabilities to improve security and stability.

References

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