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VulnerabilityPublished Updated

CVE-2026-2447: Mozilla Firefox · Heap-based Buffer Overflow

Affects Mozilla FirefoxSource CVE Database V5

0

Not known to be exploited · CVSS 8.8 High · fixed in 147.0.4 : patch Mozilla Firefox soon.

Data as of 26 Oct 2026, 08:30 UTC

CVSS 3.1 base score
8.8High
How severe the flaw is on the 0–10 CVSS scale.
EPSS
0.6% chance of exploitation in 30 days – higher than 52% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.
Patch
Available – fixed in 147.0.4
CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H

Exploitation evidence

  1. Disclosed: evidence found.

    CVE published 16 Feb 2026

  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

AI-suggested

Official fixes are available from Mozilla and should be applied immediately. Update Firefox to version 147.0.4 or later, Firefox ESR to 140.7.1 or 115.32.1 or later, and Thunderbird to 140.7.2 or 147.0.2 or later. No additional mitigation is required beyond applying these patches. Refer to Mozilla advisories MFSA 2026-10 and MFSA 2026-11 for detailed update instructions.

Description

Heap buffer overflow in libvpx. This vulnerability was fixed in Firefox 147.0.4, Firefox ESR 140.7.1, Firefox ESR 115.32.1, Thunderbird 140.7.2, and Thunderbird 147.0.2.

References

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