Relyra SAML SignatureValue not cryptographically verified -> authentication bypass

{
  "id": "5169043eb2ce5ca5b1c1fcc827c649daf6caccf4a2d61508196bf8b51e7a749e",
  "url": "https://osv.dev/vulnerability/CVE-2026-49454",
  "method": "structured",
  "payload": {
    "kind": "advisory",
    "title": "Relyra SAML SignatureValue not cryptographically verified -> authentication bypass",
    "summary": "Relyra is a strict-by-default SAML 2.0 Service Provider library for Elixir and Phoenix. Versions 1.0.0 and 1.1.0 accept forged SAML signatures because SignatureValue was not cryptographically verified before the library returned a successful authentication result. The XMLDSig trust boundary was incomplete as :public_key.verify over the exclusive-C14N canonicalized SignedInfo was not performed against the configured IdP certificate's public key, DigestValue was not recomputed over the canonicalized referenced element, and canonicalize/2 remained an unused passthrough in the signature-verification path. The result was a structure-only acceptance path where document shape and trust-source rejection could succeed without proving the signature bytes. A forged SignatureValue carrying an attacker-controlled NameID could be accepted as {:ok}. This issue has been fixed in version 1.2.0.",
    "evidence": "osv:CVE-2026-49454",
    "products": [],
    "severity": "critical",
    "structured": {
      "id": "CVE-2026-49454",
      "aliases": [
        "CVE-2026-49454",
        "GHSA-jv46-xfwm-36j7"
      ],
      "metrics": [
        {
          "type": "CVSS_V3",
          "score": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N"
        }
      ],
      "affected": [
        {
          "ranges": [
            {
              "repo": "https://github.com/sztheory/relyra",
              "type": "GIT",
              "events": [
                {
                  "introduced": "0"
                },
                {
                  "fixed": "09bd64728befb55f2c35dd272fb644e3cbe77e54"
                },
                {
                  "fixed": "2e456897af3158c175bb490ce7fc51d6241c8922"
                },
                {
                  "fixed": "8910200"
                }
              ],
              "database_specific": {
                "extracted_events": [
                  {
                    "range": [
                      {
                        "introduced": "1.0.0"
                      },
                      {
                        "fixed": "1.2.0"
                      }
                    ],
                    "source": "AFFECTED_FIELD",
                    "strategy": "StringRangeExpression"
                  },
                  {
                    "range": [
                      {
                        "fixed": "2e456897af3158c175bb490ce7fc51d6241c8922"
                      }
                    ],
                    "source": "REFERENCES_COMMIT"
                  },
                  {
                    "range": [
                      {
                        "fixed": "8910200"
                      }
                    ],
                    "source": "REFERENCES_COMMIT"
                  }
                ]
              }
            }
          ],
          "versions": [
            "v1.1.0",
            "v1.0",
            "v0.1"
          ],
          "database_specific": {
            "source": "https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-49454.json"
          }
        }
      ],
      "modified": "2026-10-28T02:30:30.504630360Z",
      "provider": "osv",
      "references": [
        "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/49xxx/CVE-2026-49454.json",
        "https://github.com/szTheory/relyra/security/advisories/GHSA-jv46-xfwm-36j7",
        "https://nvd.nist.gov/vuln/detail/CVE-2026-49454",
        "https://github.com/szTheory/relyra/commit/2e456897af3158c175bb490ce7fc51d6241c8922",
        "https://github.com/szTheory/relyra/commit/8910200"
      ],
      "provider_metadata": {
        "cwe_ids": [
          "CWE-287",
          "CWE-347"
        ],
        "cna_assigner": "GitHub_M",
        "osv_generated_from": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/49xxx/CVE-2026-49454.json"
      }
    },
    "related_cves": [
      {
        "value": "CVE-2026-49454",
        "evidence": "/id"
      }
    ],
    "security_relevant": true,
    "severity_evidence": "/severity/0/score"
  },
  "source_id": "core-osv",
  "document_id": 497632,
  "published_at": "2026-06-18T20:52:22.605+00:00"
}