{
    "dataType": "CVE_RECORD",
    "dataVersion": "5.2",
    "cveMetadata": {
        "cveId": "CVE-2026-55165",
        "assignerOrgId": "a0819718-46f1-4df5-94e2-005712e83aaa",
        "state": "PUBLISHED",
        "assignerShortName": "GitHub_M",
        "dateReserved": "2026-06-16T15:13:28.165Z",
        "datePublished": "2026-08-18T18:49:59.538Z",
        "dateUpdated": "2026-08-18T19:35:55.129Z"
    },
    "containers": {
        "cna": {
            "title": "Lemur : JWT verifier trusts attacker-supplied alg from token header — defense-in-depth gap; chain-dependent ATO with secret disclosure",
            "problemTypes": [
                {
                    "descriptions": [
                        {
                            "cweId": "CWE-347",
                            "lang": "en",
                            "description": "CWE-347: Improper Verification of Cryptographic Signature",
                            "type": "CWE"
                        }
                    ]
                }
            ],
            "metrics": [
                {
                    "cvssV3_1": {
                        "attackComplexity": "HIGH",
                        "attackVector": "NETWORK",
                        "availabilityImpact": "NONE",
                        "baseScore": 4.8,
                        "baseSeverity": "MEDIUM",
                        "confidentialityImpact": "LOW",
                        "integrityImpact": "LOW",
                        "privilegesRequired": "NONE",
                        "scope": "UNCHANGED",
                        "userInteraction": "NONE",
                        "vectorString": "CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:L/I:L/A:N",
                        "version": "3.1"
                    }
                }
            ],
            "references": [
                {
                    "name": "https://github.com/Netflix/lemur/security/advisories/GHSA-r9gp-7f88-9r54",
                    "tags": [
                        "x_refsource_CONFIRM"
                    ],
                    "url": "https://github.com/Netflix/lemur/security/advisories/GHSA-r9gp-7f88-9r54"
                },
                {
                    "name": "https://github.com/Netflix/lemur/commit/89898e665beed044cf7bd5927dfaa484e55bf242",
                    "tags": [
                        "x_refsource_MISC"
                    ],
                    "url": "https://github.com/Netflix/lemur/commit/89898e665beed044cf7bd5927dfaa484e55bf242"
                },
                {
                    "name": "https://github.com/Netflix/lemur/releases/tag/v1.9.2",
                    "tags": [
                        "x_refsource_MISC"
                    ],
                    "url": "https://github.com/Netflix/lemur/releases/tag/v1.9.2"
                }
            ],
            "affected": [
                {
                    "vendor": "Netflix",
                    "product": "lemur",
                    "versions": [
                        {
                            "version": "< 1.9.2",
                            "status": "affected"
                        }
                    ]
                }
            ],
            "providerMetadata": {
                "orgId": "a0819718-46f1-4df5-94e2-005712e83aaa",
                "shortName": "GitHub_M",
                "dateUpdated": "2026-08-18T18:49:59.538Z"
            },
            "descriptions": [
                {
                    "lang": "en",
                    "value": "Lemur manages TLS certificate creation. Prior to 1.9.2, the JWT verifier in lemur/auth/service.py:130-137 used fetch_token_header to read header_data[\"alg\"] from an unverified token and passed that attacker-controlled value to decode_with_multiple_secrets. PyJWT 2.x rejects alg=none with the configured key, so the flaw is a defense-in-depth gap rather than a direct authentication bypass in the shipped configuration. The unpinned algorithm can become exploitable after an asymmetric-signing migration through algorithm confusion, and it weakens algorithm-based anomaly detection because the token chooses the recorded value. A separate disclosure of LEMUR_TOKEN_SECRET would also permit forged HS256 tokens, although that disclosure is an independent prerequisite. The fix introduces the server-controlled LEMUR_TOKEN_ALGORITHMS allowlist and defaults it to HS256. This issue is fixed in version 1.9.2."
                }
            ],
            "source": {
                "advisory": "GHSA-r9gp-7f88-9r54",
                "discovery": "UNKNOWN"
            }
        },
        "adp": [
            {
                "references": [
                    {
                        "url": "https://github.com/Netflix/lemur/security/advisories/GHSA-r9gp-7f88-9r54",
                        "tags": [
                            "exploit"
                        ]
                    }
                ],
                "metrics": [
                    {
                        "other": {
                            "type": "ssvc",
                            "content": {
                                "timestamp": "2026-08-18T19:35:36.998493Z",
                                "id": "CVE-2026-55165",
                                "options": [
                                    {
                                        "Exploitation": "poc"
                                    },
                                    {
                                        "Automatable": "no"
                                    },
                                    {
                                        "Technical Impact": "partial"
                                    }
                                ],
                                "role": "CISA Coordinator",
                                "version": "2.0.3"
                            }
                        }
                    }
                ],
                "title": "CISA ADP Vulnrichment",
                "providerMetadata": {
                    "orgId": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
                    "shortName": "CISA-ADP",
                    "dateUpdated": "2026-08-18T19:35:55.129Z"
                }
            }
        ]
    }
}