CVE-2025-9179: Mozilla Firefox · Memory Buffer Overflow
Affects Mozilla FirefoxSource CVE Database V5
Not known to be exploited · CVSS 9.8 Critical : upgrade to 142 as a priority.
Data as of 26 Oct 2026, 06:26 UTC
- EPSS
- 0.6% chance of exploitation in 30 days – higher than 49% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.
- Patch
- Available – fixed in 142
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:HExploitation evidence
Disclosed: evidence found.
CVE published 19 Aug 2025
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 2026-10-26.
What to do
Upgrade Mozilla Firefox to 142.
Affected software
| Product | Affected | Fixed in |
|---|---|---|
| Mozilla Firefox | Affected
| Fixed in
|
AI-suggested
Official fixes for this vulnerability are available and have been released by Mozilla. Users and administrators should update to Firefox 142, Firefox ESR 115.27 (or later ESR versions 128.14, 140.2), Thunderbird 142, Thunderbird 128.14, or Thunderbird 140.2 to remediate this issue. Applying these updates will mitigate the vulnerability. No additional mitigation steps are required beyond applying the official patches.
Description
An attacker was able to perform memory corruption in the GMP process which processes encrypted media. This process is also heavily sandboxed, but represents slightly different privileges from the content process. This vulnerability was fixed in Firefox 142, Firefox ESR 115.27, Firefox ESR 128.14, Firefox ESR 140.2, Thunderbird 142, Thunderbird 128.14, and Thunderbird 140.2.
References
- bugzilla.mozilla.org/show_bug.cgi?id=1979527 (opens in a new tab)
- mozilla.org/security/advisories/mfsa2025-64/ (opens in a new tab)
- mozilla.org/security/advisories/mfsa2025-65/ (opens in a new tab)
- mozilla.org/security/advisories/mfsa2025-66/ (opens in a new tab)
- mozilla.org/security/advisories/mfsa2025-67/ (opens in a new tab)
- mozilla.org/security/advisories/mfsa2025-70/ (opens in a new tab)
- mozilla.org/security/advisories/mfsa2025-71/ (opens in a new tab)
- mozilla.org/security/advisories/mfsa2025-72/ (opens in a new tab)
- lists.debian.org/debian-lts-announce/2025/08/msg00018.html (opens in a new tab)
- lists.debian.org/debian-lts-announce/2025/08/msg00016.html (opens in a new tab)