What’s Vulnerable › Vulnerabilities

CVE-2026-79772: Nokogiri before 1.19.1 Unchecked Return Value canonicalize

• Severity: medium (CVSS 5.3 v3.1)
• Exploited in the wild: not listed in CISA KEV
• EPSS: 0.3% probability of exploitation in the next 30 days
• Public exploit or detection template: none known
• Published: 2026-08-25 · updated 2026-09-01
• Weakness: CWE-252

Description

Nokogiri versions before 1.19.1 fail to check the return value from xmlC14NExecute in the canonicalize method, returning an empty string on failure instead of raising an exception. Attackers can exploit this to bypass signature validation in downstream SAML libraries by providing invalid canonicalized XML that is incorrectly accepted as valid.

Affected products

• sparklemotion nokogiri: from 1.5.1 before 1.19.1 — fixed in 1.19.1
• Rubygems Nokogiri: from 1.5.1 before 1.19.1; 1.10.0, 1.10.0.rc1, 1.10.1, 1.10.10, 1.10.2, 1.10.3 (+149) — fixed in 1.19.1

How to fix

Upgrade to a fixed version: sparklemotion nokogiri 1.19.1; Rubygems Nokogiri 1.19.1. Check the vendor advisory for mitigations.

References

• https://github.com/sparklemotion/nokogiri/security/advisories/GHSA-wx95-c6cv-8532
• https://www.vulncheck.com/advisories/nokogiri-before-unchecked-return-value-canonicalize

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