TI-2025-40988 Aliases CVE-2025-66578 GHSA-c4cc-x928-vjw9

robrichards/xmlseclibs has an Libxml2 Canonicalization error which can bypass Digest/Signature validation

LOW 32CWE-248Published 2025-12-09 · Updated 2025-12-09

Key facts

Attack vector: Network
Privileges required: None
User interaction: None
Attack complexity: Low
Impact type: Denial of service
Confidentiality · integrity · availability: None · High · None
Fix status: Fixed

Attack profile from CVSS 3.1 · NVD. Fix status from CNA and GitHub. Impact type from CWE-248.

Summary

xmlseclibs is a library written in PHP for working with XML Encryption and Signatures. Versions 3.1.3 contain an authentication bypass vulnerability due to a flaw in the libxml2 canonicalization process during document transformation. When libxml2’s canonicalization is invoked on an invalid XML input, it may return an empty string rather than a canonicalized node. xmlseclibs then proceeds to compute the DigestValue over this empty string, treating it as if canonicalization succeeded. This issue is fixed in version 3.1.4. Workarounds include treating canonicalization failures (exceptions or nil/empty outputs) as fatal and aborting validation, and/or adding explicit checks to reject when canonicalize returns nil/empty or raises errors.

Why it matters now

Exploitation None reported CISA SSVC · not in CISA KEV

EPSS 0.0024 15th percentileScored 2026-11-07

Public exploit Yes 1 exploit referenceTagged by NVD

Fix Fixed xmlseclibs (robrichards): 3.1.4robrichards/xmlseclibs (Packagist): 3.1.4

SSVC decision points

CISA ADP · SSVC 2.0.3

Exploitation: None
Automatable: No
Technical impact: Partial

The decision (Track, Attend, Act) also depends on your mission and well-being impact; see CISA's SSVC guide.

Affected products

Vendor	Product	Affected versions	Fixed in	Status	Source
robrichards	xmlseclibs	before 3.1.4	3.1.4	Patch available	CNA
—	robrichards/xmlseclibs (Packagist)	before 3.1.4	3.1.4	Patch available	GHSA-c4cc-x928-vjw9

xmlseclibs Vendorrobrichards Affected before 3.1.4 Fixed in 3.1.4 Patch available CNA
robrichards/xmlseclibs (Packagist) Vendor— Affected before 3.1.4 Fixed in 3.1.4 Patch available GHSA-c4cc-x928-vjw9

CPE configurations NVD · 1

CPE	Versions	Role	Vendor
cpe:2.3:a:xmlseclibs_project:xmlseclibs::::::::	before 3.1.4	Vulnerable	Xmlseclibs Project

cpe:2.3:a:xmlseclibs_project:xmlseclibs:*:*:*:*:*:*:*:* Versions before 3.1.4 Vulnerable ·Xmlseclibs Project

Remediation

Fix · CNA xmlseclibs (robrichards) Fixed in 3.1.4
Fix · GHSA-c4cc-x928-vjw9 robrichards/xmlseclibs (Packagist) Fixed in 3.1.4 Advisory →

Timeline

2026-10-02 Threatist record created from CVE-2025-66578
2026-10-03 Alias added: GHSA-c4cc-x928-vjw9

References

Other 2

TI-2026-24841 xmlseclibs is Missing AES-GCM Authentication Tag Validation on Encrypted Nodes Allows for Unauthorized Decryption CVSS 3.1HIGH 8.2
TI-2019-02593 Improper signature verification in Rob Richards XmlSecLibs CVSS 3.1HIGH 8.8

Sources

This product uses the NVD API but is not endorsed or certified by the NVD. Sources and licences