Critical
ruby-saml vulnerable to SAML authentication bypass due to DOCTYPE handling (parser differential)
Type: advisorySources: OSV
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.
- Products
- Not specified
- Affected versions
- Not specified
- Fixed versions
- Not specified
- CVEs
- CVE-2025-25291
- Confirmed fixed CVEs
- Not specified
- Updated in this feed
- 3 Nov 2026, 14:34 UTC · Revision 1
Source evidence
ruby-saml vulnerable to SAML authentication bypass due to DOCTYPE handling (parser differential)
core-osv · Original sourcePublished 12 Mar 2025, 20:16 UTC
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.
osv:CVE-2025-25291
Complete source record
{
"id": "384281a2b41da3e8c74804482c01242e090a99e665b78328937d00443b1fa906",
"url": "https://osv.dev/vulnerability/CVE-2025-25291",
"method": "structured",
"payload": {
"kind": "advisory",
"title": "ruby-saml vulnerable to SAML authentication bypass due to DOCTYPE handling (parser differential)",
"summary": "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.",
"evidence": "osv:CVE-2025-25291",
"products": [],
"severity": "critical",
"structured": {
"id": "CVE-2025-25291",
"aliases": [
"BIT-gitlab-2025-25291",
"CVE-2025-25291",
"GHSA-4vc4-m8qh-g8jm"
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"metrics": [
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"type": "CVSS_V4",
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}
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{
"cpe": "cpe:2.3:a:onelogin:ruby-saml:*:*:*:*:*:*:*:*",
"range": [
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{
"range": [
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"source": "REFERENCES_COMMIT"
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{
"range": [
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"source": "REFERENCES_COMMIT"
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{
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"source": "REFERENCES_TAG",
"original_tag": "v1.12.4"
},
{
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"original_tag": "v1.18.0"
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"versions": [
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"v1.10.4",
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"v2.1.1",
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"v1.9.0",
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"v1.4.0",
"v1.3.1",
"v1.3.0",
"v1.2.0",
"v1.1.0",
"v1.0.0",
"v0.9.2",
"v0.9.1",
"v0.9.0",
"v1.12.3",
"v1.17.0",
"v1.12.2",
"v1.16.0",
"v1.15.0",
"v1.14.0",
"v1.12.1",
"v1.12.0",
"v1.11.0",
"v1.7.2",
"v1.7.1",
"v1.6.2",
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"database_specific": {
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],
"modified": "2026-10-28T02:30:29.522541123Z",
"provider": "osv",
"references": [
"https://about.gitlab.com/releases/2025/03/12/patch-release-gitlab-17-9-2-released",
"https://github.com/SAML-Toolkits/ruby-saml/releases/tag/v1.12.4",
"https://github.com/SAML-Toolkits/ruby-saml/releases/tag/v1.18.0",
"https://lists.debian.org/debian-lts-announce/2025/04/msg00011.html",
"https://news.ycombinator.com/item?id=43374519",
"https://portswigger.net/research/saml-roulette-the-hacker-always-wins",
"https://github.com/CVEProject/cvelistV5/tree/main/cves/2025/25xxx/CVE-2025-25291.json",
"https://github.com/SAML-Toolkits/ruby-saml/security/advisories/GHSA-4vc4-m8qh-g8jm",
"https://github.com/omniauth/omniauth-saml/security/advisories/GHSA-hw46-3hmr-x9xv",
"https://nvd.nist.gov/vuln/detail/CVE-2025-25291",
"https://security.netapp.com/advisory/ntap-20250314-0010/",
"https://securitylab.github.com/advisories/GHSL-2024-329_GHSL-2024-330_ruby-saml",
"https://github.com/SAML-Toolkits/ruby-saml/commit/e76c5b36bac40aedbf1ba7ffaaf495be63328cd9",
"https://github.com/SAML-Toolkits/ruby-saml/commit/e9c1cdbd0f9afa467b585de279db0cbd0fb8ae97",
"https://github.blog/security/sign-in-as-anyone-bypassing-saml-sso-authentication-with-parser-differentials"
],
"provider_metadata": {
"cwe_ids": [
"CWE-347",
"CWE-436"
],
"cna_assigner": "GitHub_M",
"osv_generated_from": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2025/25xxx/CVE-2025-25291.json"
}
},
"related_cves": [
{
"value": "CVE-2025-25291",
"evidence": "/id"
}
],
"security_relevant": true,
"severity_evidence": "/severity/0/score"
},
"source_id": "core-osv",
"document_id": 496408,
"published_at": "2025-03-12T20:16:12.181+00:00"
}