{
    "dataType": "CVE_RECORD",
    "dataVersion": "5.2",
    "cveMetadata": {
        "cveId": "CVE-2026-34831",
        "assignerOrgId": "a0819718-46f1-4df5-94e2-005712e83aaa",
        "state": "PUBLISHED",
        "assignerShortName": "GitHub_M",
        "dateReserved": "2026-03-30T20:52:53.284Z",
        "datePublished": "2026-04-02T16:43:08.762Z",
        "dateUpdated": "2026-04-03T17:48:11.330Z"
    },
    "containers": {
        "cna": {
            "title": "Rack: Content-Length mismatch in Rack::Files error responses",
            "problemTypes": [
                {
                    "descriptions": [
                        {
                            "cweId": "CWE-130",
                            "lang": "en",
                            "description": "CWE-130: Improper Handling of Length Parameter Inconsistency",
                            "type": "CWE"
                        }
                    ]
                },
                {
                    "descriptions": [
                        {
                            "cweId": "CWE-135",
                            "lang": "en",
                            "description": "CWE-135: Incorrect Calculation of Multi-Byte String Length",
                            "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/rack/rack/security/advisories/GHSA-q2ww-5357-x388",
                    "tags": [
                        "x_refsource_CONFIRM"
                    ],
                    "url": "https://github.com/rack/rack/security/advisories/GHSA-q2ww-5357-x388"
                }
            ],
            "affected": [
                {
                    "vendor": "rack",
                    "product": "rack",
                    "versions": [
                        {
                            "version": "< 2.2.23",
                            "status": "affected"
                        },
                        {
                            "version": ">= 3.0.0.beta1, < 3.1.21",
                            "status": "affected"
                        },
                        {
                            "version": ">= 3.2.0, < 3.2.6",
                            "status": "affected"
                        }
                    ]
                }
            ],
            "providerMetadata": {
                "orgId": "a0819718-46f1-4df5-94e2-005712e83aaa",
                "shortName": "GitHub_M",
                "dateUpdated": "2026-04-02T16:43:08.762Z"
            },
            "descriptions": [
                {
                    "lang": "en",
                    "value": "Rack is a modular Ruby web server interface. Prior to versions 2.2.23, 3.1.21, and 3.2.6, Rack::Files#fail sets the Content-Length response header using String#size instead of String#bytesize. When the response body contains multibyte UTF-8 characters, the declared Content-Length is smaller than the number of bytes actually sent on the wire. Because Rack::Files reflects the requested path in 404 responses, an attacker can trigger this mismatch by requesting a non-existent path containing percent-encoded UTF-8 characters. This results in incorrect HTTP response framing and may cause response desynchronization in deployments that rely on the incorrect Content-Length value. This issue has been patched in versions 2.2.23, 3.1.21, and 3.2.6."
                }
            ],
            "source": {
                "advisory": "GHSA-q2ww-5357-x388",
                "discovery": "UNKNOWN"
            }
        },
        "adp": [
            {
                "metrics": [
                    {
                        "other": {
                            "type": "ssvc",
                            "content": {
                                "timestamp": "2026-04-03T17:43:52.462237Z",
                                "id": "CVE-2026-34831",
                                "options": [
                                    {
                                        "Exploitation": "none"
                                    },
                                    {
                                        "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": "2026-04-03T17:48:11.330Z"
                }
            }
        ]
    }
}