High
SimpleSAMLphp SAML2 library has incorrect signature verification for HTTP-Redirect binding
Type: advisorySources: OSV
The SimpleSAMLphp SAML2 library is a PHP library for SAML2 related functionality. Prior to versions 4.17.0 and 5.0.0-alpha.20, there is a signature confusion attack in the HTTPRedirect binding. An attacker with any signed SAMLResponse via the HTTP-Redirect binding can cause the application to accept an unsigned message. Versions 4.17.0 and 5.0.0-alpha.20 contain a fix for the issue.
- Products
- Not specified
- Affected versions
- Not specified
- Fixed versions
- Not specified
- CVEs
- CVE-2025-27773
- Confirmed fixed CVEs
- Not specified
- Updated in this feed
- 3 Nov 2026, 05:54 UTC · Revision 1
Source evidence
SimpleSAMLphp SAML2 library has incorrect signature verification for HTTP-Redirect binding
core-osv · Original sourcePublished 11 Mar 2025, 19:04 UTC
The SimpleSAMLphp SAML2 library is a PHP library for SAML2 related functionality. Prior to versions 4.17.0 and 5.0.0-alpha.20, there is a signature confusion attack in the HTTPRedirect binding. An attacker with any signed SAMLResponse via the HTTP-Redirect binding can cause the application to accept an unsigned message. Versions 4.17.0 and 5.0.0-alpha.20 contain a fix for the issue.
osv:CVE-2025-27773
Complete source record
{
"id": "74fe3bc564f8b9127d87968ff3e67d825bdd9291e9858ce0dda92c4242abc836",
"url": "https://osv.dev/vulnerability/CVE-2025-27773",
"method": "structured",
"payload": {
"kind": "advisory",
"title": "SimpleSAMLphp SAML2 library has incorrect signature verification for HTTP-Redirect binding",
"summary": "The SimpleSAMLphp SAML2 library is a PHP library for SAML2 related functionality. Prior to versions 4.17.0 and 5.0.0-alpha.20, there is a signature confusion attack in the HTTPRedirect binding. An attacker with any signed SAMLResponse via the HTTP-Redirect binding can cause the application to accept an unsigned message. Versions 4.17.0 and 5.0.0-alpha.20 contain a fix for the issue.",
"evidence": "osv:CVE-2025-27773",
"products": [],
"severity": "high",
"structured": {
"id": "CVE-2025-27773",
"aliases": [
"CVE-2025-27773",
"GHSA-46r4-f8gj-xg56"
],
"metrics": [
{
"type": "CVSS_V3",
"score": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:N/I:H/A:N"
}
],
"affected": [
{
"ranges": [
{
"repo": "https://github.com/simplesamlphp/saml2",
"type": "GIT",
"events": [
{
"introduced": "0"
},
{
"fixed": "bdf16d1021363a0819c35806124a20e74a78c2c9"
},
{
"introduced": "94d4c0736656b8fb7390cc6258b692f84ed5bae5"
},
{
"fixed": "d35d41ba4b47b083b53d87fc541d5336c8743916"
},
{
"fixed": "7867d6099dc7f31bed1ea10e5bea159c5623d2a0"
}
],
"database_specific": {
"extracted_events": [
{
"range": [
{
"introduced": "0"
},
{
"fixed": "4.17.0"
}
],
"source": "AFFECTED_FIELD",
"strategy": "StringRangeExpression"
},
{
"range": [
{
"introduced": "5.0.0-alpha.1"
},
{
"fixed": "5.0.0-alpha.20"
}
],
"source": "AFFECTED_FIELD",
"strategy": "StringRangeExpression"
},
{
"range": [
{
"fixed": "7867d6099dc7f31bed1ea10e5bea159c5623d2a0"
}
],
"source": "REFERENCES_COMMIT"
}
]
}
}
],
"versions": [
"v4.6.15",
"v5.0.0-alpha.19",
"v5.0.0-alpha.18",
"v4.6.14",
"v4.16.14",
"v4.6.13",
"v4.6.12",
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"v5.0.0-alpha.16",
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"4.6.9",
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"v4.1.6",
"v4.1.5",
"v4.1.4",
"v4.1.3",
"v4.1.2",
"v4.1.1",
"v4.1.0",
"v4.0.3",
"v4.0.2",
"v4.0.1",
"v4.0.0",
"v3.4.0",
"v3.3.6",
"v3.3.5",
"v3.3.4",
"v3.3.3",
"v3.3.2",
"v3.3.0",
"v3.2.6",
"v3.2.5",
"v3.2.4",
"v3.2.3",
"v3.2.2",
"v3.2.1",
"v3.2",
"v3.1.6",
"v3.1.5",
"v3.1.4",
"v3.1.3",
"v3.1.2",
"v3.1.1",
"v3.1.0",
"v3.0.3",
"v3.0.2",
"v3.0.1",
"v3.0.0",
"v2.0.0",
"v1.7.1",
"v0.8.1",
"v1.7.0",
"v0.8.0",
"v1.6.1",
"v0.7.1",
"v1.6.0",
"v0.7.0",
"v1.5.4",
"v0.6.4",
"v1.5.3",
"v0.6.3",
"1.5.3",
"v1.5.2",
"v0.6.2",
"v1.5.1",
"v0.6.1",
"v1.5.0",
"v0.6.0",
"v1.4.0",
"v0.5.0",
"v1.3.2",
"v0.4.2",
"v1.3.1",
"v0.4.1",
"v1.3.0",
"v0.4.0",
"v1.2.0",
"v0.3.0",
"v1.1.0",
"v1.0.0",
"v0.1.0",
"v0.1.0-alpha"
],
"database_specific": {
"source": "https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2025-27773.json"
}
}
],
"modified": "2026-10-28T02:30:26.441761629Z",
"provider": "osv",
"references": [
"https://github.com/simplesamlphp/saml2/blob/9545abd0d9d48388f2fa00469c5c1e0294f0303e/src/SAML2/HTTPRedirect.php#L104-L113",
"https://github.com/simplesamlphp/saml2/blob/9545abd0d9d48388f2fa00469c5c1e0294f0303e/src/SAML2/HTTPRedirect.php#L178-L217",
"https://lists.debian.org/debian-lts-announce/2025/05/msg00013.html",
"https://github.com/CVEProject/cvelistV5/tree/main/cves/2025/27xxx/CVE-2025-27773.json",
"https://github.com/simplesamlphp/saml2/security/advisories/GHSA-46r4-f8gj-xg56",
"https://nvd.nist.gov/vuln/detail/CVE-2025-27773",
"https://github.com/simplesamlphp/saml2/commit/7867d6099dc7f31bed1ea10e5bea159c5623d2a0"
],
"provider_metadata": {
"cwe_ids": [
"CWE-347"
],
"cna_assigner": "GitHub_M",
"osv_generated_from": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2025/27xxx/CVE-2025-27773.json"
}
},
"related_cves": [
{
"value": "CVE-2025-27773",
"evidence": "/id"
}
],
"security_relevant": true,
"severity_evidence": "/severity/0/score"
},
"source_id": "core-osv",
"document_id": 492869,
"published_at": "2025-03-11T19:04:52.135+00:00"
}