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GHSA-x4h9-gwv3-r4m4

CriticalCVSS 9.3 / 10
Published Dec 8, 2025·Last modified Dec 12, 2025
Affected Components(0)

No affected components available

Description

Summary

Ruby-saml up to and including 1.12.4, there is an authentication bypass vulnerability because of an issue at libxml2 canonicalization process used by Nokogiri for document transformation. That allows an attacker to be able to execute a Signature Wrapping attack. The vulnerability does not affect the version 1.18.0.

Details

When libxml2’s canonicalization is invoked on an invalid XML input, it may return an empty string rather than a canonicalized node. ruby-saml then proceeds to compute the DigestValue over this empty string, treating it as if canonicalization succeeded.

Impact

  1. Digest bypass: By crafting input that causes canonicalization to yield an empty string, the attacker can manipulate validation to pass incorrectly.

  2. Signature replay on empty canonical form: If an empty string has been signed once (e.g., in a prior interaction or via a misconfigured flow), that signature can potentially be replayed to bypass authentication.

Risk Scores
Base Score
9.3

The vulnerability can be exploited over the network without needing physical access. It is easy for an attacker to exploit this vulnerability. An attacker does not need any special privileges or access rights. No user interaction is needed for the attacker to exploit this vulnerability.

Threat Intelligence
8.0

Exploitation activity has been observed. Apply available patches or mitigations urgently.

EPSS
0.21%

The exploit probability is very low. The vulnerability is unlikely to be exploited in the next 30 days.

Exploit
Not available

We did not find any exploit available. Neither in GitHub repositories nor in the Exploit-Database.

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