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VulnerabilityPublished Updated

CVE-2025-10527: Mozilla Firefox · Use After Free

Affects Mozilla FirefoxSource CVE Database V5

0

Not known to be exploited · CVSS 7.1 High : upgrade to 143 soon.

Data as of 26 Oct 2026, 14:05 UTC

CVSS 3.1 base score
7.1High
How severe the flaw is on the 0–10 CVSS scale.
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:L

Exploitation evidence

  1. Disclosed: evidence found.

    CVE published 16 Sep 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

Upgrade Mozilla Firefox to 143.

Affected software

ProductAffectedFixed in
Mozilla FirefoxAffected
  • <143
Fixed in
  • 143

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

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