What is CVE-2023-25734?

CVE-2023-25734 is a high-severity vulnerability in Microsoft Windows, classified under URL Redirection to Untrusted Site (Open Redirect). CVSS score: 8.1/10. Published 2023-06-02.

How severe is CVE-2023-25734?

High severity. CVSS v3 base score is 8.1 out of 10.

Open Redirect in Microsoft Windows

CVE-2023-25734

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, Thunderbird < 102.8, and Firefox ESR < 102.8.

Vulnerability class: Open Redirect

Published 2023-06-02 · last modified 2026-06-17.

CVSS v3 metric

CVSS v3 base score 8.1 (High). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:N.

EPSS exploit prediction

EPSS: 0.008 (54.1th percentile), scored 2026-10-01.

Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 54th percentile — 54.1% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.

EPSS over last 30 days · oldest: 0.008 · newest: 0.008 · change: 0.000

Affected products

Microsoft Windows
Mozilla Firefox — versions unspecified
Mozilla Firefox Esr — versions unspecified
Mozilla Firefox Esr
Mozilla Thunderbird — versions unspecified

Weakness classification (CWE)

CWE-601 — URL Redirection to Untrusted Site (Open Redirect)

References

www.mozilla.org/security/advisories/mfsa2023-06/ (Vendor Advisory)
www.mozilla.org/security/advisories/mfsa2023-05/ (Vendor Advisory)
www.mozilla.org/security/advisories/mfsa2023-07/ (Vendor Advisory)
bugzilla.mozilla.org/show_bug.cgi (Permissions Required, Issue Tracking)
bugzilla.mozilla.org/show_bug.cgi (Exploit, Issue Tracking, Vendor Advisory)
bugzilla.mozilla.org/show_bug.cgi (Permissions Required, Issue Tracking)
bugzilla.mozilla.org/show_bug.cgi (Permissions Required, Issue Tracking)

Frequently asked questions

What is CVE-2023-25734?: CVE-2023-25734 is a high-severity vulnerability in Microsoft Windows, classified under URL Redirection to Untrusted Site (Open Redirect). CVSS score: 8.1/10. Published 2023-06-02.
How severe is CVE-2023-25734?: High severity. CVSS v3 base score is 8.1 out of 10.