What is CVE-2025-1781?

CVE-2025-1781 is a medium-severity vulnerability in W3 CSS Validator, classified under Improper Restriction of XML External Entity Reference (XXE). CVSS score: 6.5/10. Published 2025-03-28.

How severe is CVE-2025-1781?

Medium severity. CVSS v3 base score is 6.5 out of 10.

XXE in W3 CSS Validator

CVE-2025-1781

There is a XXE in W3CSS Validator versions before cssval-20250226 that allows an attacker to use specially-crafted XML objects to coerce server-side request forgery (SSRF). This could be exploited to read arbitrary local files if an attacker has access to exception messages.

Vulnerability class: XXE (XML External Entity)

EPSS: 0.004 (29.0th percentile) — read the EPSS interpretation.

CVSS v3 metric

CVSS v3 base score 6.5 (Medium). Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:N.

Affected products

W3 Css_validator
W3c Css Validator — versions < cssval-20250226

Weakness classification (CWE)

CWE-611 — Improper Restriction of XML External Entity Reference (XXE)

References

cve-coordination@google.com (Exploit, Vendor Advisory)

Frequently asked questions

What is CVE-2025-1781?: CVE-2025-1781 is a medium-severity vulnerability in W3 CSS Validator, classified under Improper Restriction of XML External Entity Reference (XXE). CVSS score: 6.5/10. Published 2025-03-28.
How severe is CVE-2025-1781?: Medium severity. CVSS v3 base score is 6.5 out of 10.