CVE-2025-10527: Mozilla Firefox · Use After Free
Affects Mozilla FirefoxSource CVE Database V5
Not known to be exploited · CVSS 7.1 High : upgrade to 143 soon.
Data as of 26 Oct 2026, 14:05 UTC
- EPSS
- 0.2% chance of exploitation in 30 days – higher than 21% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.
- Patch
- Available – fixed in 143
CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:LExploitation evidence
Disclosed: evidence found.
CVE published 16 Sep 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 26 Oct 2026.
What to do
Upgrade Mozilla Firefox to 143.
Affected software
| Product | Affected | Fixed in |
|---|---|---|
| Mozilla Firefox | Affected
| Fixed in
|
AI-suggested
Mozilla has released official fixes for this vulnerability in Firefox 143, Firefox ESR 140.3, Thunderbird 143, and Thunderbird ESR 140.3. Users and administrators should update to these versions or later to remediate the issue. Since the vulnerability is fixed in these releases, no additional mitigation steps are required beyond applying the official updates.
Description
Sandbox escape due to use-after-free in the Graphics: Canvas2D component. This vulnerability was fixed in Firefox 143, Firefox ESR 140.3, Thunderbird 143, and Thunderbird 140.3.
References
- bugzilla.mozilla.org/show_bug.cgi?id=1984825 (opens in a new tab)
- mozilla.org/security/advisories/mfsa2025-73/ (opens in a new tab)
- mozilla.org/security/advisories/mfsa2025-75/ (opens in a new tab)
- mozilla.org/security/advisories/mfsa2025-77/ (opens in a new tab)
- mozilla.org/security/advisories/mfsa2025-78/ (opens in a new tab)
- lists.debian.org/debian-lts-announce/2025/09/msg00026.html (opens in a new tab)
- lists.debian.org/debian-lts-announce/2025/09/msg00020.html (opens in a new tab)