CVE-2023-25734 — After downloading a Windows <code>

After downloading a Windows <code>.url</code> shortcut from the local filesystem, an attacker could supply a remote path that would lead to unexpected network requests from the operating system. This also had the potential to leak NTLM credentials to the resource.<

01What is this vulnerability?

After downloading a Windows <code>.url</code> shortcut from the local filesystem, an attacker could supply a remote path that would lead to unexpected network requests from the operating system. This also had the potential to leak NTLM credentials to the resource.<br>*This bug only affects Firefox on Windows. Other operating systems are unaffected.*. This vulnerability affects Firefox < 110…

02Affected products

Vendor	Product	Versions
Mozilla	Firefox	unspecified
Mozilla	Thunderbird	unspecified
Mozilla	Firefox ESR	unspecified

03Active exploitation status

Not currently listed on the CISA Known Exploited Vulnerabilities (KEV) catalog. EPSS is the best forward-looking signal — see the EPSS row above.

04Recommended remediation

• Patch to a fixed version listed in the vendor advisory (see references below).
• Mitigate with WAF rules, network egress filters, or feature flags where the patch is not yet available.
• Hunt historical logs for exploitation indicators — see Detection signatures below.

05Technical details

For the full vendor write-up, exploit chains, and reference implementations, see the references list in section 09.

06Detection signatures

Ask SARA in chat to draft a starting detection for this CVE in your stack of choice.

07Related CVEs

No directly-cited follow-up CVEs in the KB record for this advisory. The references list in section 09 carries the vendor cross-references.

08Timeline

• Published: 2023-06-02T00:00:00.000Z
• Last modified: 2025-01-09T21:03:44.768Z

09References

• www.mozilla.org — https://www.mozilla.org/security/advisories/mfsa2023-06/
• www.mozilla.org — https://www.mozilla.org/security/advisories/mfsa2023-05/
• www.mozilla.org — https://www.mozilla.org/security/advisories/mfsa2023-07/
• bugzilla.mozilla.org — https://bugzilla.mozilla.org/show_bug.cgi?id=1809923
• bugzilla.mozilla.org — https://bugzilla.mozilla.org/show_bug.cgi?id=1784451
• bugzilla.mozilla.org — https://bugzilla.mozilla.org/show_bug.cgi?id=1810143
• bugzilla.mozilla.org — https://bugzilla.mozilla.org/show_bug.cgi?id=1812338