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Vulnerability details: VCID-18ax-mp8x-n7ap
Vulnerability ID VCID-18ax-mp8x-n7ap
Aliases CVE-2023-49087
GHSA-ww7x-3gxh-qm6r
Summary Validation of SignedInfo 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: ![afbeelding](https://user-images.githubusercontent.com/841045/285817284-a7b7b3b4-768a-46e8-a34b-61790b6e23a5.png) 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.
Status Published
Exploitability 0.5
Weighted Severity 8.0
Risk 4.0
Affected and Fixed Packages Package Details
Weaknesses (3)
CWE-1035 OWASP Top Ten 2017 Category A9 - Using Components with Known Vulnerabilities
CWE-345 Insufficient Verification of Data Authenticity
CWE-937 OWASP Top Ten 2013 Category A9 - Using Components with Known Vulnerabilities
System Score Found at
cvssv3 6.8 https://access.redhat.com/hydra/rest/securitydata/cve/CVE-2023-49087.json
epss 0.00205 https://api.first.org/data/v1/epss?cve=CVE-2023-49087
epss 0.00205 https://api.first.org/data/v1/epss?cve=CVE-2023-49087
cvssv3.1 7.5 https://github.com/simplesamlphp/xml-security
generic_textual HIGH https://github.com/simplesamlphp/xml-security
cvssv3.1 7.5 https://github.com/simplesamlphp/xml-security/blob/master/src/XML/SignedElementTrait.php
generic_textual HIGH https://github.com/simplesamlphp/xml-security/blob/master/src/XML/SignedElementTrait.php
cvssv3.1 7.5 https://github.com/simplesamlphp/xml-security/commit/f509e3083dd7870cce5880c804b5122317287581
generic_textual HIGH https://github.com/simplesamlphp/xml-security/commit/f509e3083dd7870cce5880c804b5122317287581
cvssv3.1 7.5 https://github.com/simplesamlphp/xml-security/security/advisories/GHSA-ww7x-3gxh-qm6r
generic_textual HIGH https://github.com/simplesamlphp/xml-security/security/advisories/GHSA-ww7x-3gxh-qm6r
cvssv3.1 7.5 https://nvd.nist.gov/vuln/detail/CVE-2023-49087
generic_textual HIGH https://nvd.nist.gov/vuln/detail/CVE-2023-49087
Reference id Reference type URL
https://access.redhat.com/hydra/rest/securitydata/cve/CVE-2023-49087.json
https://api.first.org/data/v1/epss?cve=CVE-2023-49087
https://github.com/simplesamlphp/xml-security
https://github.com/simplesamlphp/xml-security/blob/master/src/XML/SignedElementTrait.php
https://github.com/simplesamlphp/xml-security/commit/f509e3083dd7870cce5880c804b5122317287581
https://nvd.nist.gov/vuln/detail/CVE-2023-49087
2252245 https://bugzilla.redhat.com/show_bug.cgi?id=2252245
GHSA-ww7x-3gxh-qm6r https://github.com/advisories/GHSA-ww7x-3gxh-qm6r
GHSA-ww7x-3gxh-qm6r https://github.com/simplesamlphp/xml-security/security/advisories/GHSA-ww7x-3gxh-qm6r
No exploits are available.
Vector: CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:C/C:N/I:H/A:N Found at https://access.redhat.com/hydra/rest/securitydata/cve/CVE-2023-49087.json
Attack Vector (AV) Attack Complexity (AC) Privileges Required (PR) User Interaction (UI) Scope (S) Confidentiality Impact (C) Integrity Impact (I) Availability Impact (A)

network

adjacent_network

local

physical

low

high

none

low

high

none

required

unchanged

changed

high

low

none

high

low

none

high

low

none
Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N Found at https://github.com/simplesamlphp/xml-security
Attack Vector (AV) Attack Complexity (AC) Privileges Required (PR) User Interaction (UI) Scope (S) Confidentiality Impact (C) Integrity Impact (I) Availability Impact (A)

network

adjacent_network

local

physical

low

high

none

low

high

none

required

unchanged

changed

high

low

none

high

low

none

high

low

none
Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N Found at https://github.com/simplesamlphp/xml-security/blob/master/src/XML/SignedElementTrait.php
Attack Vector (AV) Attack Complexity (AC) Privileges Required (PR) User Interaction (UI) Scope (S) Confidentiality Impact (C) Integrity Impact (I) Availability Impact (A)

network

adjacent_network

local

physical

low

high

none

low

high

none

required

unchanged

changed

high

low

none

high

low

none

high

low

none
Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N Found at https://github.com/simplesamlphp/xml-security/commit/f509e3083dd7870cce5880c804b5122317287581
Attack Vector (AV) Attack Complexity (AC) Privileges Required (PR) User Interaction (UI) Scope (S) Confidentiality Impact (C) Integrity Impact (I) Availability Impact (A)

network

adjacent_network

local

physical

low

high

none

low

high

none

required

unchanged

changed

high

low

none

high

low

none

high

low

none
Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N Found at https://github.com/simplesamlphp/xml-security/security/advisories/GHSA-ww7x-3gxh-qm6r
Attack Vector (AV) Attack Complexity (AC) Privileges Required (PR) User Interaction (UI) Scope (S) Confidentiality Impact (C) Integrity Impact (I) Availability Impact (A)

network

adjacent_network

local

physical

low

high

none

low

high

none

required

unchanged

changed

high

low

none

high

low

none

high

low

none
Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N Found at https://nvd.nist.gov/vuln/detail/CVE-2023-49087
Attack Vector (AV) Attack Complexity (AC) Privileges Required (PR) User Interaction (UI) Scope (S) Confidentiality Impact (C) Integrity Impact (I) Availability Impact (A)

network

adjacent_network

local

physical

low

high

none

low

high

none

required

unchanged

changed

high

low

none

high

low

none

high

low

none
Exploit Prediction Scoring System (EPSS)
Percentile 0.42629
EPSS Score 0.00205
Published At June 5, 2026, 12:55 p.m.
Date Actor Action Source VulnerableCode Version
2026-06-02T04:46:28.878950+00:00 GitLab Importer Import https://gitlab.com/gitlab-org/advisories-community/-/blob/main/packagist/simplesamlphp/saml2/CVE-2023-49087.yml 38.6.0