{
    "dataType": "CVE_RECORD",
    "dataVersion": "5.2",
    "cveMetadata": {
        "cveId": "CVE-2026-90668",
        "assignerOrgId": "8254265b-2729-46b6-b9e3-3dfca2d5bfca",
        "state": "PUBLISHED",
        "assignerShortName": "mitre",
        "dateReserved": "2026-09-13T02:00:53.718Z",
        "datePublished": "2026-09-13T02:00:54.190Z",
        "dateUpdated": "2026-09-13T02:00:54.190Z"
    },
    "containers": {
        "cna": {
            "affected": [
                {
                    "defaultStatus": "unaffected",
                    "modules": [
                        "webserver"
                    ],
                    "product": "UnrealIRCd",
                    "programFiles": [
                        "src/modules/webserver.c"
                    ],
                    "programRoutines": [
                        {
                            "name": "webserver_handle_request_header()"
                        }
                    ],
                    "repo": "https://github.com/unrealircd/unrealircd",
                    "vendor": "UnrealIRCd",
                    "versions": [
                        {
                            "lessThan": "6.2.7",
                            "status": "affected",
                            "version": "6.0.5",
                            "versionType": "semver"
                        }
                    ]
                }
            ],
            "configurations": [
                {
                    "lang": "en",
                    "supportingMedia": [
                        {
                            "base64": false,
                            "type": "text/html",
                            "value": "A websocket or rpc listener is enabled (listen::options::websocket or listen::options::rpc)."
                        }
                    ],
                    "value": "A websocket or rpc listener is enabled (listen::options::websocket or listen::options::rpc)."
                }
            ],
            "descriptions": [
                {
                    "lang": "en",
                    "value": "The webserver in UnrealIRCd 6.0.5 through 6.2.6 before 6.2.7 does not limit the number of HTTP request headers, which allows remote attackers to cause a denial of service (memory consumption and unresponsive server) via an HTTP request with an unlimited number of headers, if a websocket or JSON-RPC listener is enabled (disabled by default)."
                }
            ],
            "metrics": [
                {
                    "cvssV4_0": {
                        "Automatable": "YES",
                        "Recovery": "AUTOMATIC",
                        "Safety": "NOT_DEFINED",
                        "attackComplexity": "LOW",
                        "attackRequirements": "NONE",
                        "attackVector": "NETWORK",
                        "baseScore": 8.7,
                        "baseSeverity": "HIGH",
                        "privilegesRequired": "NONE",
                        "providerUrgency": "NOT_DEFINED",
                        "subAvailabilityImpact": "NONE",
                        "subConfidentialityImpact": "NONE",
                        "subIntegrityImpact": "NONE",
                        "userInteraction": "NONE",
                        "valueDensity": "NOT_DEFINED",
                        "vectorString": "CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N/AU:Y/R:A/RE:L",
                        "version": "4.0",
                        "vulnAvailabilityImpact": "HIGH",
                        "vulnConfidentialityImpact": "NONE",
                        "vulnIntegrityImpact": "NONE",
                        "vulnerabilityResponseEffort": "LOW"
                    },
                    "format": "CVSS",
                    "scenarios": [
                        {
                            "lang": "en",
                            "value": "GENERAL"
                        }
                    ]
                },
                {
                    "cvssV3_1": {
                        "attackComplexity": "LOW",
                        "attackVector": "NETWORK",
                        "availabilityImpact": "HIGH",
                        "baseScore": 7.5,
                        "baseSeverity": "HIGH",
                        "confidentialityImpact": "NONE",
                        "integrityImpact": "NONE",
                        "privilegesRequired": "NONE",
                        "scope": "UNCHANGED",
                        "userInteraction": "NONE",
                        "vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H",
                        "version": "3.1"
                    },
                    "format": "CVSS",
                    "scenarios": [
                        {
                            "lang": "en",
                            "value": "GENERAL"
                        }
                    ]
                }
            ],
            "problemTypes": [
                {
                    "descriptions": [
                        {
                            "cweId": "CWE-770",
                            "description": "CWE-770 Allocation of Resources Without Limits or Throttling",
                            "lang": "en",
                            "type": "CWE"
                        }
                    ]
                }
            ],
            "providerMetadata": {
                "orgId": "8254265b-2729-46b6-b9e3-3dfca2d5bfca",
                "shortName": "mitre",
                "dateUpdated": "2026-09-13T02:00:54.190Z"
            },
            "references": [
                {
                    "url": "https://www.unrealircd.org/"
                },
                {
                    "url": "https://forums.unrealircd.org/viewtopic.php?t=9483"
                }
            ],
            "solutions": [
                {
                    "lang": "en",
                    "supportingMedia": [
                        {
                            "base64": false,
                            "type": "text/html",
                            "value": "Upgrade to UnrealIRCd 6.2.7 or later. Alternatively, apply the hot-patch to fix the issue without restart: ./unrealircd hot-patch webserver-header-dos<br><br>"
                        }
                    ],
                    "value": "Upgrade to UnrealIRCd 6.2.7 or later. Alternatively, apply the hot-patch to fix the issue without restart: ./unrealircd hot-patch webserver-header-dos"
                }
            ],
            "workarounds": [
                {
                    "lang": "en",
                    "supportingMedia": [
                        {
                            "base64": false,
                            "type": "text/html",
                            "value": "Remove the websocket and rpc options from your listen blocks until the patch or upgrade is applied.<br><br>"
                        }
                    ],
                    "value": "Remove the websocket and rpc options from your listen blocks until the patch or upgrade is applied."
                }
            ],
            "x_generator": {
                "engine": "CVE-Request-form 0.0.1"
            },
            "cpeApplicability": [
                {
                    "nodes": [
                        {
                            "operator": "OR",
                            "negate": false,
                            "cpeMatch": [
                                {
                                    "vulnerable": true,
                                    "criteria": "cpe:2.3:a:unrealircd:unrealircd:*:*:*:*:*:*:*:*",
                                    "versionStartIncluding": "6.0.5",
                                    "versionEndExcluding": "6.2.7"
                                }
                            ]
                        }
                    ]
                }
            ]
        }
    }
}