CVE-2025-66578: xmlseclibs is a library written in PHP for working with XML Encryption and Signatures

Q: How do I fix CVE-2025-66578?

xmlseclibs: upgrade to 3.1.4. Exact commands for each OS are on this page.

Q: Is CVE-2025-66578 being exploited?

CVE-2025-66578 is not on the CISA Known Exploited Vulnerabilities list at the time of the last update. Check again, as this can change.

Q: What does CVE-2025-66578 affect?

CVE-2025-66578 affects xmlseclibs. Severity is medium (CVSS 6.0). 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

Q: How urgent is CVE-2025-66578?

Priority 30/100. Public exploit reference

Routine

MEDIUM 6.0UPGRADE

CVE-2025-66578 is a medium-severity flaw (CVSS 6.0) affecting xmlseclibs. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.

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, treatin

Why this priority

Public exploit reference

A fixed release or distro patch exists.

Risk facts

CVSS score	6.0 (Medium)
Attack vector	Network (remote)
Attack complexity	Low
Privileges needed	High
User interaction	None
EPSS exploit chance	0.2% (top 85%)
CISA exploited list	No
Weakness	CWE-248
Published	2025-12-09
Last modified	2026-10-07

Publisher (CNA): GitHub, Inc. · Vendor: xmlseclibs project

Last updated 2026-10-07 · Sources: CVE Program, NVD, CISA KEV, EPSS and vendor advisories · How we score

Am I affected?

Timeline

2025-12-09 16:18 UTCPublished CVE record published
2026-10-07 20:10 UTCUpdated Record last modified

xmlseclibs project xmlseclibs UPGRADE

Affected: < 3.1.4

Fixed in: 3.1.4

Safe to downgrade to: no unaffected older release

1. Check installed version

apt-cache policy xmlseclibs || rpm -q xmlseclibs || xmlseclibs --version

2. UPGRADE to 3.1.4 (Debian / Ubuntu)

sudo apt update && sudo apt install --only-upgrade xmlseclibs

2. UPGRADE (RHEL / Amazon Linux / Fedora)

sudo dnf upgrade xmlseclibs

Note

Distros often backport fixes without changing the version number. Confirm with the distro advisory or changelog.

Verify at the official source NVD · CVE Program · Report a problem with this page
Scores and fixes here are computed automatically from those and other public sources. Confirm with the vendor advisory before changing production systems.

Quick answers

How do I fix CVE-2025-66578?

xmlseclibs: upgrade to 3.1.4. Exact commands for each OS are on this page.

Is CVE-2025-66578 being exploited?

CVE-2025-66578 is not on the CISA Known Exploited Vulnerabilities list at the time of the last update. Check again, as this can change.

What does CVE-2025-66578 affect?

CVE-2025-66578 affects xmlseclibs. Severity is medium (CVSS 6.0). 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

How urgent is CVE-2025-66578?

Priority 30/100. Public exploit reference

Software pages

PHP vulnerabilities · libxml2 vulnerabilities

Related CVEs

CVE-2026-32313 HIGH 8.2 UPGRADE xmlseclibs is a library written in PHP for working with XML Encryption and Signatures

References

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