CVE-2025-66567
ruby-saml has a SAML authentication bypass due to namespace handling (parser differential)
The ruby-saml library is for implementing the client side of a SAML authorization. ruby-saml versions up to and including 1.12.4 contain an authentication bypass vulnerability due to an incomplete fix for CVE-2025-25292. ReXML and Nokogiri parse XML differently, generating entirely different document structures from the same input. This allows an attacker to execute a Signature Wrapping attack. This issue is fixed in version 1.18.0.
Attack profile
How easy it is to exploit
- Attack vector
- Network
- Complexity
- Low
- Privileges needed
- None
- User interaction
- None
What an attacker can affect
- Confidentiality
- High
- Integrity
- High
- Availability
- None
Exploit likelihood
What each source reports
CVE List Score used
ruby-saml has a SAML authentication bypass due to namespace handling (parser differential)
The ruby-saml library is for implementing the client side of a SAML authorization. ruby-saml versions up to and including 1.12.4 contain an authentication bypass vulnerability due to an incomplete fix for CVE-2025-25292. ReXML and Nokogiri parse XML differently, generating entirely different document structures from the same input. This allows an attacker to execute a Signature Wrapping attack. This issue is fixed in version 1.18.0.
- Record
CVE-2025-66567- CVSS 4.0
- 9.3 Critical
CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:N/SC:N/SI:N/SA:N - Weakness
- CWE-347
- Updated
- 2026-11-02
EUVDEUVD-2025-201812
The ruby-saml library is for implementing the client side of a SAML authorization. ruby-saml versions up to and including 1.12.4 contain an authentication bypass vulnerability due to an incomplete fix for CVE-2025-25292. ReXML and Nokogiri parse XML differently, generating entirely different document structures from the same input. This allows an attacker to execute a Signature Wrapping attack. This issue is fixed in version 1.18.0.
- Record
EUVD-2025-201812- CVSS 4.0
- 9.3 Critical
CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:N/SC:N/SI:N/SA:N - Updated
- 2026-11-02
GitHub AdvisoriesGHSA-9v8j-x534-2fx3
Ruby-saml has a SAML authentication bypass due to namespace handling (parser differential)
Summary
Ruby-saml up to and including 1.12.4, there is an authentication bypass vulnerability because of an incomplete fix for CVE-2025-25292. 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. The vulnerability does not affect the version 1.18.0.
Impact
That allows an attacker to be able to execute a Signature Wrapping attack and bypass the authentication
- Record
GHSA-9v8j-x534-2fx3- CVSS 4.0
- 9.3 Critical
CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:N/SC:N/SI:N/SA:N - Weakness
- CWE-347
- Updated
- 2026-11-02
NVD
The ruby-saml library is for implementing the client side of a SAML authorization. ruby-saml versions up to and including 1.12.4 contain an authentication bypass vulnerability due to an incomplete fix for CVE-2025-25292. ReXML and Nokogiri parse XML differently, generating entirely different document structures from the same input. This allows an attacker to execute a Signature Wrapping attack. This issue is fixed in version 1.18.0.
- Record
CVE-2025-66567- CVSS 4.0
- 9.3 Critical
CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:N/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X - CVSS 3.1
- 9.1 Critical
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N - Weakness
- CWE-347
- Updated
- 2026-11-02
OSV
ruby-saml has a SAML authentication bypass due to namespace handling (parser differential)
The ruby-saml library is for implementing the client side of a SAML authorization. ruby-saml versions up to and including 1.12.4 contain an authentication bypass vulnerability due to an incomplete fix for CVE-2025-25292. ReXML and Nokogiri parse XML differently, generating entirely different document structures from the same input. This allows an attacker to execute a Signature Wrapping attack. This issue is fixed in version 1.18.0.
- Record
CVE-2025-66567- CVSS 4.0
- 9.3 Critical
CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:N/SC:N/SI:N/SA:N - Weakness
- CWE-347
- Updated
- 2026-11-02
OSVGHSA-9v8j-x534-2fx3
Ruby-saml has a SAML authentication bypass due to namespace handling (parser differential)
Summary
Ruby-saml up to and including 1.12.4, there is an authentication bypass vulnerability because of an incomplete fix for CVE-2025-25292. 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. The vulnerability does not affect the version 1.18.0.
Impact
That allows an attacker to be able to execute a Signature Wrapping attack and bypass the authentication
- Record
GHSA-9v8j-x534-2fx3- CVSS 4.0
- 9.3 Critical
CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:N/SC:N/SI:N/SA:N - Weakness
- CWE-347
- Updated
- 2026-11-02
OSVUBUNTU-CVE-2025-66567
The ruby-saml library is for implementing the client side of a SAML authorization. ruby-saml versions up to and including 1.12.4 contain an authentication bypass vulnerability due to an incomplete fix for CVE-2025-25292. ReXML and Nokogiri parse XML differently, generating entirely different document structures from the same input. This allows an attacker to execute a Signature Wrapping attack. This issue is fixed in version 1.18.0.
- Record
UBUNTU-CVE-2025-66567- CVSS 4.0
- 9.3 Critical
CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:N/SC:N/SI:N/SA:N - CVSS 3.1
- 9.1 Critical
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N - Updated
- 2026-11-02
Affected products
Affected packages
| Package | Affected | Fixed |
|---|---|---|
ruby-samlRubyGems |
before 1.18.0 | 1.18.0 |
ruby-samlRubyGems |
before 1.18.0, plus listed versions 0.0.50.0.60.0.70.0.80.2.1 Show 45 moreShow less0.2.20.2.30.3.00.3.10.3.20.3.30.3.40.4.00.4.10.4.20.4.30.4.40.4.50.4.60.4.70.5.00.5.10.5.20.5.30.6.00.7.00.7.10.7.20.7.30.8.00.8.10.8.100.8.110.8.120.8.130.8.140.8.150.8.160.8.170.8.180.8.20.8.30.8.40.8.50.8.60.8.70.8.80.8.90.90.9.1 |
1.18.0 |
ruby-samlUbuntu:Pro:16.04:LTS |
All versions, plus listed versions 0.9.2-11.0.0-11.1.2-1ubuntu11.1.2-1ubuntu1+esm11.1.2-1ubuntu1+esm2 |
None known |
ruby-samlUbuntu:Pro:18.04:LTS |
All versions, plus listed versions 1.4.1-11.7.2-11.7.2-1ubuntu0.1~esm11.7.2-1ubuntu0.1~esm2 |
None known |
ruby-samlUbuntu:Pro:20.04:LTS |
All versions, plus listed versions 1.7.2-11.11.0-11.11.0-1ubuntu0.11.11.0-1ubuntu0.1+esm1 |
None known |
ruby-samlUbuntu:Pro:22.04:LTS |
All versions, plus listed versions 1.11.0-11.13.0-11.13.0-1ubuntu0.11.13.0-1ubuntu0.1+esm1 |
None known |
ruby-samlUbuntu:Pro:24.04:LTS |
All versions, plus listed versions 1.15.0-11.15.0-1ubuntu0.24.04.11.15.0-1ubuntu0.24.04.1+esm1 |
None known |
History
| Recorded | Changed | Sources |
|---|---|---|
| first indexed | CVE List, EUVD, GitHub Advisories, NVD, OSV |
Dates are when Every CVE recorded each change. Upstream dates may differ.
In short
CVE-2025-66567 is a critical vulnerability (CVSS 9.3) in Onelogin Ruby-saml, published December 8, 2025. No source lists public exploit code. EPSS puts the chance of exploitation in the next 30 days at 0.42%, the 36th percentile. Fixed in ruby-saml 1.18.0.
References
github.com/SAML-Toolkits/ruby-saml/security/advisories/GHSA-9v8j-x534-2fx3
nvd.nist.gov/vuln/detail/CVE-2025-66567
Left out here: 37 versions. The JSON record has them.