Bug 2523567 (CVE-2026-79772)

Summary: CVE-2026-79772 nokogiri: Nokogiri: Signature validation bypass via unchecked return value
Product: [Other] Security Response Reporter: OSIDB Bzimport <bzimport>
Component: vulnerabilityAssignee: Product Security DevOps Team <prodsec-dev>
Status: NEW --- QA Contact:
Severity: medium Docs Contact:
Priority: medium    
Version: unspecifiedCC: akostadi, amasferr, anthomas, crizzo, dmayorov, ehelms, eshamard, ggainey, jlledo, jpasqual, juwatts, jvasik, kaycoth, mdellweg, mhulan, nmoumoul, osousa, pantinor, pcreech, rblanco, rchan, smallamp, tmalecek, tsedmik
Target Milestone: ---Keywords: Security
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Hardware: All   
OS: Linux   
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A flaw was found in Nokogiri. This vulnerability occurs because the `canonicalize` method fails to properly check the return value from an internal XML processing function, returning an empty string on failure instead of an error. A remote attacker could exploit this by providing specially crafted XML, leading to a bypass of signature validation in Security Assertion Markup Language (SAML) libraries that rely on Nokogiri, potentially allowing malicious data to be accepted as legitimate.
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oVirt Team: --- RHEL 7.3 requirements from Atomic Host:
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Bug Depends On: 2525151, 2525149    
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Description OSIDB Bzimport 2026-08-25 15:34:42 UTC 
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.