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CVE-2025-1935VulnerabilityPublished Updated

CVE-2025-1935: Mozilla Firefox · Cross-site Scripting

Affects Mozilla FirefoxSource CVE Database V5

0

Not known to be exploited · CVSS 4.3 Medium : upgrade to 136 when convenient.

Data as of 26 Oct 2026, 06:26 UTC

CVSS 3.1 base score
4.3Medium
How severe the flaw is on the 0–10 CVSS scale.
EPSS
0.3% chance of exploitation in 30 days – higher than 27% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.
Patch
Available – fixed in 136
CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:L/I:N/A:N

Exploitation evidence

  1. Disclosed: evidence found.

    CVE published 4 Mar 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 2026-10-26.

What to do

Upgrade Mozilla Firefox to 136.

Affected software

ProductAffectedFixed in
Mozilla FirefoxAffected
  • <136
Fixed in
  • 136

AI-suggested

Mozilla has released official fixes for this vulnerability in Firefox 136 and Firefox ESR 128.8. Users and administrators should update affected Firefox and Thunderbird versions to these or later releases to remediate the issue. Since the vulnerability requires user interaction and is fixed in the latest versions, no additional mitigation steps are necessary beyond applying the official update.

Description

A web page could trick a user into setting that site as the default handler for a custom URL protocol. This vulnerability was fixed in Firefox 136, Firefox ESR 128.8, Thunderbird 136, and Thunderbird 128.8.

References

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