CVE-2025-1781Public exploitNetwork attack vector

SSRF via enabled SAX external entities

Published Mar 28, 2025 · Updated Mar 28, 2025

XXE in W3C CSS Validation Service before cssval-20250226 allows remote authenticated users to trigger SSRF with crafted XML. XMLStyleSheetHandler.parse leaves SAX external parameter and general entities enabled, so entity references dereference attacker-selected URLs during XML parsing. SSRF is direct; local-file disclosure additionally requires access to exception messages and a system DTD suitable for error-based extraction.

CVSS severity8.4
High
EPSS probability0.38%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
Coverage for this vulnerability

See if you're affected

Explore vulnerability checks for your environment with Hinoki.

Book a demo

Summary

What happened

XXE in W3C CSS Validation Service before cssval-20250226 allows remote authenticated users to trigger SSRF with crafted XML. XMLStyleSheetHandler.parse leaves SAX external parameter and general entities enabled, so entity references dereference attacker-selected URLs during XML parsing. SSRF is direct; local-file disclosure additionally requires access to exception messages and a system DTD suitable for error-based extraction.

The record

CVE
CVE-2025-1781
Published
Mar 28, 2025
Updated
Mar 28, 2025
Vendor
World Wide Web Consortium (W3C)
Product
W3C CSS Validation Service
Classifications
CWE-611, CAPEC-228, T1190
Attack vector
network
Privileges
authenticated

Timeline

How it unfolded

  1. Mar 28, 2025CVE publishedPublication date reported by the CVE source.
  2. Mar 28, 2025Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

Compare your product and version with the public record. A matching version still requires validation against your environment.

Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=< cssval-20250226

What conditions does exploitation require?

Attack vectornetwork
Required privilegesauthenticated

What is affected?

World Wide Web Consortium (W3C) · W3C CSS Validation Serviceversion=< cssval-20250226

Published CVSS scores

8.4Google Inc.CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:N/VI:H/VA:L/SC:N/SI:H/SA:L
6.5NIST NVDCVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:N

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

Daily unique IPsNo honeypot observations are available for this CVE in the selected window.

No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesauthenticated
Known exploitationUnconfirmed
Public exploitPublished

Weakness, pattern, technique

CWE-611Improper Restriction of XML External Entity Reference
CAPEC-228DTD Injection
T1190Exploit Public-Facing Application

Public exploit references

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

See the directory against your own environment.

Your stack

Check the software in your environment

Book a demo to see how Hinoki identifies affected software and validates exploitability in your environment.

Book a demo