Authentication bypass in ruby-saml via libxml2 canonicalization empty-string digest (Signature Wrapping)
ruby-saml (client-side SAML implementation) is vulnerable to an authentication bypass in versions up to and including 1.12.4 due to incorrect handling of libxml2 canonicalization errors during XML Signature processing via Nokogiri. When libxml2 canonicalization is invoked on invalid XML input, it may return an empty string instead of a canonicalized node. ruby-saml then computes the DigestValue over this empty string and proceeds as if canonicalization succeeded, enabling a Signature Wrapping-style attack that can desynchronize signature verification from the assertion ultimately processed by application logic. The issue is fixed in ruby-saml 1.18.0.
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Exploits
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Recent activity
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A Ruby-SAML vulnerability (pre-1.18.0, including 1.12.4) tied to the paper’s described SAML signature-validation bypass techniques (parser inconsistencies / canonicalization-related bypasses).
A critical authentication bypass vulnerability in the ruby-saml library due to improper handling of XML canonicalization, allowing attackers to perform Signature Wrapping attacks and bypass SAML signature validation.
A critical authentication bypass vulnerability in the Ruby SAML library.
The version that knows your environment.
Query your assets running an affected version, and investigate the blast radius.
Every observed campaign linking this CVE to a named adversary.
Malware families riding this exploit, with evidence and IOCs.
YARA, Sigma, Snort, and vendor rules, auto-deployed to your SIEM.
Cross-references every affected SKU, including bundled OEM variants.
Community discussion across Reddit, Mastodon, and other social sources.