{
    "dataType": "CVE_RECORD",
    "dataVersion": "5.2",
    "cveMetadata": {
        "cveId": "CVE-2026-21876",
        "assignerOrgId": "a0819718-46f1-4df5-94e2-005712e83aaa",
        "state": "PUBLISHED",
        "assignerShortName": "GitHub_M",
        "dateReserved": "2026-01-05T17:24:36.927Z",
        "datePublished": "2026-01-08T13:55:37.102Z",
        "dateUpdated": "2026-04-09T15:41:17.073Z"
    },
    "containers": {
        "cna": {
            "title": "OWASP CRS has multipart bypass using multiple content-type parts",
            "problemTypes": [
                {
                    "descriptions": [
                        {
                            "cweId": "CWE-794",
                            "lang": "en",
                            "description": "CWE-794: Incomplete Filtering of Multiple Instances of Special Elements",
                            "type": "CWE"
                        }
                    ]
                }
            ],
            "metrics": [
                {
                    "cvssV3_1": {
                        "attackComplexity": "LOW",
                        "attackVector": "NETWORK",
                        "availabilityImpact": "NONE",
                        "baseScore": 9.3,
                        "baseSeverity": "CRITICAL",
                        "confidentialityImpact": "HIGH",
                        "integrityImpact": "LOW",
                        "privilegesRequired": "NONE",
                        "scope": "CHANGED",
                        "userInteraction": "NONE",
                        "vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:L/A:N",
                        "version": "3.1"
                    }
                }
            ],
            "references": [
                {
                    "name": "https://github.com/coreruleset/coreruleset/security/advisories/GHSA-36fv-25j3-r2c5",
                    "tags": [
                        "x_refsource_CONFIRM"
                    ],
                    "url": "https://github.com/coreruleset/coreruleset/security/advisories/GHSA-36fv-25j3-r2c5"
                },
                {
                    "name": "https://github.com/coreruleset/coreruleset/commit/80d80473abf71bd49bf6d3c1ab221e3c74e4eb83",
                    "tags": [
                        "x_refsource_MISC"
                    ],
                    "url": "https://github.com/coreruleset/coreruleset/commit/80d80473abf71bd49bf6d3c1ab221e3c74e4eb83"
                },
                {
                    "name": "https://github.com/coreruleset/coreruleset/commit/9917985de09a6cf38b3261faf9105e909d67a7d6",
                    "tags": [
                        "x_refsource_MISC"
                    ],
                    "url": "https://github.com/coreruleset/coreruleset/commit/9917985de09a6cf38b3261faf9105e909d67a7d6"
                },
                {
                    "name": "https://github.com/coreruleset/coreruleset/releases/tag/v3.3.8",
                    "tags": [
                        "x_refsource_MISC"
                    ],
                    "url": "https://github.com/coreruleset/coreruleset/releases/tag/v3.3.8"
                },
                {
                    "name": "https://github.com/coreruleset/coreruleset/releases/tag/v4.22.0",
                    "tags": [
                        "x_refsource_MISC"
                    ],
                    "url": "https://github.com/coreruleset/coreruleset/releases/tag/v4.22.0"
                }
            ],
            "affected": [
                {
                    "vendor": "coreruleset",
                    "product": "coreruleset",
                    "versions": [
                        {
                            "version": "< 4.22.0",
                            "status": "affected"
                        },
                        {
                            "version": "< 3.3.8",
                            "status": "affected"
                        }
                    ]
                }
            ],
            "providerMetadata": {
                "orgId": "a0819718-46f1-4df5-94e2-005712e83aaa",
                "shortName": "GitHub_M",
                "dateUpdated": "2026-01-08T13:55:37.102Z"
            },
            "descriptions": [
                {
                    "lang": "en",
                    "value": "The OWASP core rule set (CRS) is a set of generic attack detection rules for use with compatible web application firewalls. Prior to versions 4.22.0 and 3.3.8, the current rule 922110 has a bug when processing multipart requests with multiple parts. When the first rule in a chain iterates over a collection (like `MULTIPART_PART_HEADERS`), the capture variables (`TX:0`, `TX:1`) get overwritten with each iteration. Only the last captured value is available to the chained rule, which means malicious charsets in earlier parts can be missed if a later part has a legitimate charset. Versions 4.22.0 and 3.3.8 patch the issue."
                }
            ],
            "source": {
                "advisory": "GHSA-36fv-25j3-r2c5",
                "discovery": "UNKNOWN"
            }
        },
        "adp": [
            {
                "references": [
                    {
                        "url": "https://github.com/daytriftnewgen/CVE-2026-21876",
                        "tags": [
                            "exploit"
                        ]
                    }
                ],
                "metrics": [
                    {
                        "other": {
                            "type": "ssvc",
                            "content": {
                                "timestamp": "2026-01-08T14:52:48.615550Z",
                                "id": "CVE-2026-21876",
                                "options": [
                                    {
                                        "Exploitation": "none"
                                    },
                                    {
                                        "Automatable": "yes"
                                    },
                                    {
                                        "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": "2026-04-09T15:41:17.073Z"
                }
            }
        ]
    }
}