CVE-2023-49087 is a high-severity security vulnerability in simplesamlphp/xml-security (composer), affecting versions = 1.6.11. It is fixed in 1.6.12, 5.0.0-alpha.13.
Validation of an XML Signature requires verification that the hash value of the related XML-document (after any optional transformations and/or normalizations) matches a specific DigestValue-value, but also that the cryptografic signature on the SignedInfo-tree (the one that contains the DigestValue) verifies and matches a trusted public key. Within the simpleSAMLphp/xml-security library (https://github.com/simplesamlphp/xml-security), the hash is being validated using SignedElementTrait::validateReference, and the signature is being verified in SignedElementTrait::verifyInternal https://github.com/simplesamlphp/xml-security/blob/master/src/XML/SignedElementTrait.php: What stands out is that the signature is being calculated over the canonical version of the SignedInfo-tree. The validateReference method, however, uses the original non-canonicalized version of SignedInfo. Impact If an attacker somehow (i.e. by exploiting a bug in PHP's canonicalization function) manages to manipulate the canonicalized version's DigestValue, it would be potentially be possible to forge the signature. No possibilities to exploit this were found during the investigation.
CVE-2023-49087 has a CVSS score of 7.5 (High). The vector is network-reachable, no privileges required, and no user interaction. A CVSS score reflects the worst-case severity of the vulnerability, not your specific exposure. Whether this affects your application depends on whether the vulnerable code is present and reachable in your environment.
A fixed version is available (1.6.12, 5.0.0-alpha.13). Upgrading removes the vulnerable code path.
composer
simplesamlphp/xml-security (= 1.6.11)simplesamlphp/saml2 (= 5.0.0-alpha.12)simplesamlphp/xml-security → 1.6.12 (composer)simplesamlphp/saml2 → 5.0.0-alpha.13 (composer)Severity tells you how bad this could be in the worst case. It does not tell you whether you are exposed. Exploitability and impact are functions of runtime truth: whether the vulnerable code is present, reachable, and actually executes in your application. A vulnerable package can sit in your dependency tree and never run.
Kodem, an Intelligent Application Security platform, uses runtime intelligence to reveal which vulnerabilities actually execute in production, so teams prioritize the ones that genuinely matter instead of chasing every advisory.
Kodem's runtime-powered SCA identifies whether CVE-2023-49087 is reachable in your applications. Explore open-source security for your team.
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Already deployed Kodem? See CVE-2023-49087 in your environment →Upgrade the following packages to resolve this vulnerability:
simplesamlphp/xml-security to 1.6.12 or latersimplesamlphp/saml2 to 5.0.0-alpha.13 or laterKodem Kai can prioritize this vulnerability in your dependency tree and generate a fix recommendation.
CVE-2023-49087 is a high-severity security vulnerability in simplesamlphp/xml-security (composer), affecting versions = 1.6.11. It is fixed in 1.6.12, 5.0.0-alpha.13.
CVE-2023-49087 has a CVSS score of 7.5 (High). This score reflects the worst-case severity of the vulnerability, not your specific exposure. Whether it represents real risk in your environment depends on whether the vulnerable code is present and reachable.
simplesamlphp/xml-security (composer) (versions = 1.6.11)simplesamlphp/saml2 (composer) (versions = 5.0.0-alpha.12)Yes. CVE-2023-49087 is fixed in 1.6.12, 5.0.0-alpha.13. Upgrade to this version or later.
Whether CVE-2023-49087 is exploitable in your environment depends on whether the vulnerable code is present and reachable. A CVSS score is a worst-case rating; it does not account for your specific deployment, configuration, or usage patterns. Kodem, an Intelligent Application Security platform, uses runtime intelligence to show which vulnerabilities actually execute in production, so you can focus on the ones that represent real risk. Get a demo
Exploitability and impact are not fixed properties of a CVE. They depend on runtime truth: whether the vulnerable code is present, reachable, and actually executes in your application. A high CVSS score on a dependency that never runs is not the same as real risk. Kodem, an Intelligent Application Security platform, uses runtime intelligence to reveal which vulnerabilities actually execute in production, so teams prioritize the ones that genuinely matter.
simplesamlphp/xml-security to 1.6.12 or latersimplesamlphp/saml2 to 5.0.0-alpha.13 or later