{
    "dataType": "CVE_RECORD",
    "dataVersion": "5.2",
    "cveMetadata": {
        "cveId": "CVE-2026-49265",
        "assignerOrgId": "a0819718-46f1-4df5-94e2-005712e83aaa",
        "state": "PUBLISHED",
        "assignerShortName": "GitHub_M",
        "dateReserved": "2026-05-28T14:33:01.180Z",
        "datePublished": "2026-10-13T15:47:11.854Z",
        "dateUpdated": "2026-10-13T16:19:39.092Z"
    },
    "containers": {
        "cna": {
            "title": "OAuthLib: Timing Attack Vulnerability in PKCE code_verifier Comparison",
            "problemTypes": [
                {
                    "descriptions": [
                        {
                            "cweId": "CWE-208",
                            "lang": "en",
                            "description": "CWE-208: Observable Timing Discrepancy",
                            "type": "CWE"
                        }
                    ]
                }
            ],
            "metrics": [
                {
                    "cvssV3_1": {
                        "attackComplexity": "HIGH",
                        "attackVector": "NETWORK",
                        "availabilityImpact": "NONE",
                        "baseScore": 6.8,
                        "baseSeverity": "MEDIUM",
                        "confidentialityImpact": "HIGH",
                        "integrityImpact": "HIGH",
                        "privilegesRequired": "NONE",
                        "scope": "UNCHANGED",
                        "userInteraction": "REQUIRED",
                        "vectorString": "CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:U/C:H/I:H/A:N",
                        "version": "3.1"
                    }
                }
            ],
            "references": [
                {
                    "name": "https://github.com/oauthlib/oauthlib/security/advisories/GHSA-xpv3-w29h-x7cv",
                    "tags": [
                        "x_refsource_CONFIRM"
                    ],
                    "url": "https://github.com/oauthlib/oauthlib/security/advisories/GHSA-xpv3-w29h-x7cv"
                },
                {
                    "name": "https://github.com/oauthlib/oauthlib/pull/963",
                    "tags": [
                        "x_refsource_MISC"
                    ],
                    "url": "https://github.com/oauthlib/oauthlib/pull/963"
                },
                {
                    "name": "https://github.com/oauthlib/oauthlib/commit/74664d3fe037a354e180e305135c6bab1747a6b0",
                    "tags": [
                        "x_refsource_MISC"
                    ],
                    "url": "https://github.com/oauthlib/oauthlib/commit/74664d3fe037a354e180e305135c6bab1747a6b0"
                },
                {
                    "name": "https://github.com/oauthlib/oauthlib/releases/tag/v4.0.0",
                    "tags": [
                        "x_refsource_MISC"
                    ],
                    "url": "https://github.com/oauthlib/oauthlib/releases/tag/v4.0.0"
                },
                {
                    "name": "https://github.com/pypa/advisory-database/tree/main/vulns/oauthlib/PYSEC-2026-4114.yaml",
                    "tags": [
                        "x_refsource_MISC"
                    ],
                    "url": "https://github.com/pypa/advisory-database/tree/main/vulns/oauthlib/PYSEC-2026-4114.yaml"
                }
            ],
            "affected": [
                {
                    "vendor": "oauthlib",
                    "product": "oauthlib",
                    "versions": [
                        {
                            "version": ">= 3.0.0, < 4.0.0",
                            "status": "affected"
                        }
                    ]
                }
            ],
            "providerMetadata": {
                "orgId": "a0819718-46f1-4df5-94e2-005712e83aaa",
                "shortName": "GitHub_M",
                "dateUpdated": "2026-10-13T15:47:11.854Z"
            },
            "descriptions": [
                {
                    "lang": "en",
                    "value": "OAuthLib is an implementation of the OAuth request-signing logic for Python 3.6+. From 3.0.0 until 4.0.0, OAuthLib's PKCE checks in oauthlib/oauth2/rfc6749/grant_types/authorization_code.py compare attacker-supplied code_verifier values with stored challenges using ordinary string equality in code_challenge_method_plain and code_challenge_method_s256. Because the comparison can return after a length difference or the first mismatching character, repeated token endpoint measurements can reveal common-prefix timing information that could potentially allow recovery of the code_verifier, unauthorized access-token acquisition, and account takeover. Practical exploitation requires an intercepted, single-use authorization code and enough measurements to overcome real-world network noise; the local timing benchmark does not establish practical remote account takeover, so the weakness remains a defense-in-depth concern. This issue is fixed in version 4.0.0."
                }
            ],
            "source": {
                "advisory": "GHSA-xpv3-w29h-x7cv",
                "discovery": "UNKNOWN"
            }
        },
        "adp": [
            {
                "metrics": [
                    {
                        "other": {
                            "type": "ssvc",
                            "content": {
                                "timestamp": "2026-10-13T16:19:32.600149Z",
                                "id": "CVE-2026-49265",
                                "options": [
                                    {
                                        "Exploitation": "none"
                                    },
                                    {
                                        "Automatable": "no"
                                    },
                                    {
                                        "Technical Impact": "total"
                                    }
                                ],
                                "role": "CISA Coordinator",
                                "version": "2.0.3"
                            }
                        }
                    }
                ],
                "title": "CISA ADP Vulnrichment",
                "providerMetadata": {
                    "orgId": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
                    "shortName": "CISA-ADP",
                    "dateUpdated": "2026-10-13T16:19:39.092Z"
                }
            }
        ]
    }
}