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CVE-2025-10529VulnerabilityPublished Updated

CVE-2025-10529: Mozilla Firefox · Vulnerability

Affects Mozilla FirefoxSource CVE Database V5

0

Not known to be exploited · CVSS 6.5 Medium : upgrade to 143 when convenient.

Data as of 25 Oct 2026, 19:02 UTC

CVSS 3.1 base score
6.5Medium
How severe the flaw is on the 0–10 CVSS scale.
EPSS
0.3% chance of exploitation in 30 days – higher than 22% 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:N/S:U/C:L/I:L/A:N

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 2026-10-25.

What to do

Upgrade Mozilla Firefox to 143.

Affected software

ProductAffectedFixed in
Mozilla FirefoxAffected
  • <143
Fixed in
  • 143

AI-suggested

Mozilla has released official patches fixing this vulnerability in Firefox 143 and Firefox ESR 140.3. Users and administrators should update their Firefox installations to these versions or later to remediate the vulnerability. Since this is a client-side browser vulnerability, applying the official update is the primary and recommended mitigation. No additional vendor-recommended mitigations or workarounds are indicated.

Description

Same-origin policy bypass in the Layout component. This vulnerability was fixed in Firefox 143, Firefox ESR 140.3, Thunderbird 143, and Thunderbird 140.3.

References

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