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CVE-2025-25291

ruby-saml vulnerable to SAML authentication bypass due to DOCTYPE handling (parser differential)

Public exploit available. Not confirmed exploited in the wild yet. Fixed versions are out.

CVSS 3.19.8CriticalEPSS percentile98th21% chance in 30 daysCISA KEVNot listedNo confirmed exploitation
Public exploit: 1 sourceFix5 products2 fixed builds listed below
Check it yourself

Nuclei · 1 templateOpenVAS · 3 checks

e.g. GitLab - SAML Authentication Bypass · OID 1.3.6.1.4.1.25623.1.0.171295

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Published Updated Sources: CVE.org, NVD, GitHub, BDU

NVD CVE.org

What to do

Find your product and version, then upgrade to the build on the right.

  • SAML-Toolkits ruby-samlAffected: < 1.12.4Upgrade to: not statedAffected: >= 1.13.0, < 1.18.0Upgrade to: not statedStated by: CVE record
  • RubyGems ruby-samlAffected: < 1.12.4Upgrade to: 1.12.4Stated by: GitHub advisory
  • Omniauth SamlAffected: < 1.10.6Upgrade to: 1.10.6Stated by: NVD
  • Onelogin Ruby-samlAffected: < 1.12.4Upgrade to: 1.12.4Stated by: NVD
  • Сообщество свободного программного обеспечения Debian GNU/LinuxAffected: 11Upgrade to: not statedStated by: BDU

Versions as the sources state them. 3 more products have version data. Full version matrix after sign-in

Check it yourselfA free Nuclei and OpenVAS check exists for this CVE. Run it against your hosts.Is your organisation exposed?Discuss checks for your systems with a specialist. Scope is agreed before testing.

What it is

From the CVE record

ruby-saml provides security assertion markup language (SAML) single sign-on (SSO) for Ruby. An authentication bypass vulnerability was found in ruby-saml prior to versions 1.12.4 and 1.18.0 due to a parser differential. ReXML and Nokogiri parse XML differently; the parsers can generate entirely different document structures from the same XML input. That allows an attacker to be able to execute a Signature Wrapping attack. This issue may lead to authentication bypass. Versions 1.12.4 and 1.18.0 fix the issue.

In plain language

No plain-language summary for this CVE yet.

Exploitation

Where each signal puts this CVE on the scale from published to confirmed exploited.

EPSS98th
Public exploit
CISA KEV

Not in the catalog. CISA has not confirmed exploitation.

Public exploits

1 source with a proof of concept or module.

Exploit links, PoCs and Metasploit modules after sign-in
EPSS

21% chance of exploitation activity in the next 30 days, which ranks it in the 98th percentile of scored CVEs.

Exploit Prediction Scoring System, FIRST.org. A probability, not a confirmation.

Lifecycle

The patch came 123 days before any public exploit.

  1. OpenVAS check added
  2. Public exploit / PoCsource: github-poc
  3. Nuclei check added
  4. Patch availablerecord updated
  5. Publishedweakness classified, att&ck mapped

Affected products

And 2 more affected products. See all after sign-in

Technical detail

CVSS 3.1 vector

Open in the CVSS calculator

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

Scored 9.8 by NVD.

How it is reached

  • Attack Vector NetworkExploitable remotely over the network without any special conditions
  • Attack Complexity LowNo special conditions — the attack can be reliably reproduced
  • Privileges Required NoneNo authentication required — anyone can exploit this
  • User Interaction NoneNo user interaction needed — fully automated exploitation

Scope

  • Scope UnchangedImpact is limited to the vulnerable component itself

Impact if exploited

  • Confidentiality HighTotal information disclosure — all data in the component is compromised
  • Integrity HighTotal loss of integrity — attacker can modify any data in the component
  • Availability HighTotal denial of service — the component is completely unavailable

Weaknesses

ATT&CK techniques

Mapped from the weaknesses above (CWE to ATT&CK), not observed in attacks.

Sources

References in the record

And 17 more references. See all after sign-in

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We'll flag the next CVE, public exploit or patch for Ruby SAML, not every advisory. This one: public exploit.