CVE-2026-49289: Simplesamlphp/saml2 Denial of Service Vulnerability
HIGHCVE-2026-49289 is a HIGH (CVSS 7.5) denial of service vulnerability (CWE-400: Uncontrolled Resource Consumption) affecting Simplesamlphp/saml2 libraries in the Packagist ecosystem. The issue involves simplesamlphp has possible dos via xpath transform. Remediation is available by upgrading affected packages to version 4.20.3, 4.19.3.
CVE-2026-49289 at a Glance
Security Impact
CVSS: 7.5
The security impact metrics below are parsed directly from the CVSS v3.1 vector string (CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H).
How to Fix CVE-2026-49289
To remediate this vulnerability, upgrade all affected Simplesamlphp/saml2 dependencies to a patched release. Both direct and transitive dependencies should be checked, as frameworks or security libraries may pull in vulnerable versions transitively.
Upgrade simplesamlphp/saml2 to 4.20.3Upgrade simplesamlphp/saml2-legacy to 4.20.3Upgrade simplesamlphp/saml2 to 4.19.3Upgrade simplesamlphp/saml2-legacy to 4.19.3Run the following command in your project directory to verify that all resolved dependencies use the patched release:
inspect dependencies for simplesamlphp/saml2How to Check if You Are Affected
To determine whether your application is affected by CVE-2026-49289, inspect your project dependencies for Simplesamlphp/saml2:
inspect dependencies for simplesamlphp/saml2Analyze the terminal output to locate any version of Simplesamlphp/saml2 in your dependency tree. If any resolved version matches the vulnerable ranges listed in the table below (for example, versions earlier than 4.20.3), your application is affected.
Note: Verify declared build manifests and deployed runtime container environments.
Technical Details
Vulnerability Mechanism & Technical Analysis
This vulnerability is classified under CWE-400: Uncontrolled Resource Consumption, where the product does not properly control the allocation and maintenance of a limited resource. In Simplesamlphp/saml2, software state validation or input boundaries are circumvented during processing. Review the official source advisory statement below for specific affected components, classes, and reproduction details.
Source Advisory Statement
CVE-2026-49289 Affected Simplesamlphp/saml2 Versions
4 component(s)| Product / Package | Ecosystem | Affected Versions | Fixed Version |
|---|---|---|---|
|
simplesamlphp/saml2
|
Packagist |
≥ 4.20.0
< 4.20.3
|
4.20.3
|
|
simplesamlphp/saml2-legacy
|
Packagist |
≥ 4.20.0
< 4.20.3
|
4.20.3
|
|
simplesamlphp/saml2
|
Packagist |
< 4.19.3
|
4.19.3
|
|
simplesamlphp/saml2-legacy
|
Packagist |
< 4.19.3
|
4.19.3
|
References
Frequently Asked Questions
What is CVE-2026-49289?
Which Simplesamlphp/saml2 versions are affected?
What version fixes CVE-2026-49289?
Is simplesamlphp/saml2 affected?
Is simplesamlphp/saml2-legacy affected?
What is the CVSS score of CVE-2026-49289?
What CWE is associated with CVE-2026-49289?
How can I check Packagist dependencies for CVE-2026-49289?
Machine-readable OSV JSON
OSV v1.5 Schema
{
"schema_version" : "1.4.0",
"id" : "GHSA-5cjr-mxj5-wmrx",
"modified" : "2026-08-05T12:44:43Z",
"published" : "2026-07-02T20:27:23Z",
"aliases" : [ "CVE-2026-49289" ],
"summary" : "SimpleSAMLphp has Possible DoS via XPath Transform",
"details" : "## Summary\n\nThis library turned out to be vulnerable to Denial-of-Service attacks using XPath transforms. A mitigation has been put in place to restrict the number of transforms and to restrict transforms to only the transform-algorithms mentioned in the SAML 2.0 Core Specifications (and specifically refuse XPath transforms).\n\n## Impact\n\nAn attacker is able to send specially crafted messages to any entity relying on SimpleSAMLphp (or directly on this SAML2-library) to be able to perform a Denial-of-Service attack.",
"severity" : [ {
"type" : "CVSS_V3",
"score" : "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H"
} ],
"affected" : [ {
"package" : {
"ecosystem" : "Packagist",
"name" : "simplesamlphp/saml2"
},
"ranges" : [ {
"type" : "ECOSYSTEM",
"events" : [ {
"introduced" : "4.20.0"
}, {
"fixed" : "4.20.3"
} ]
} ],
"database_specific" : {
"last_known_affected_version_range" : "<= 4.20.2"
}
}, {
"package" : {
"ecosystem" : "Packagist",
"name" : "simplesamlphp/saml2-legacy"
},
"ranges" : [ {
"type" : "ECOSYSTEM",
"events" : [ {
"introduced" : "4.20.0"
}, {
"fixed" : "4.20.3"
} ]
} ],
"database_specific" : {
"last_known_affected_version_range" : "<= 4.20.2"
}
}, {
"package" : {
"ecosystem" : "Packagist",
"name" : "simplesamlphp/saml2"
},
"ranges" : [ {
"type" : "ECOSYSTEM",
"events" : [ {
"introduced" : "0"
}, {
"fixed" : "4.19.3"
} ]
} ],
"database_specific" : {
"last_known_affected_version_range" : "<= 4.19.2"
}
}, {
"package" : {
"ecosystem" : "Packagist",
"name" : "simplesamlphp/saml2-legacy"
},
"ranges" : [ {
"type" : "ECOSYSTEM",
"events" : [ {
"introduced" : "0"
}, {
"fixed" : "4.19.3"
} ]
} ],
"database_specific" : {
"last_known_affected_version_range" : "<= 4.19.2"
}
} ],
"references" : [ {
"type" : "WEB",
"url" : "https://github.com/simplesamlphp/saml2/security/advisories/GHSA-5cjr-mxj5-wmrx"
}, {
"type" : "PACKAGE",
"url" : "https://github.com/simplesamlphp/saml2"
} ],
"database_specific" : {
"cwe_ids" : [ "CWE-400" ],
"severity" : "HIGH",
"github_reviewed" : true,
"github_reviewed_at" : "2026-07-02T20:27:23Z",
"nvd_published_at" : null
}
}