{"id":"CVE-2026-90668","state":"PUBLISHED","title":"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 c","description":"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).","publishedAt":"2026-09-13T02:00:54.190Z","updatedAt":"2026-09-14T18:13:44.948Z","severity":{"score":8.7,"label":"High","version":"4.0","vector":"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","source":"mitre"},"assigner":"mitre","products":["UnrealIRCd UnrealIRCd"],"affected":[{"vendor":"UnrealIRCd","product":"UnrealIRCd","defaultStatus":"unaffected","versions":[{"version":"6.0.5","status":"affected","lessThan":"6.2.7","versionType":"semver"}],"modules":["webserver"],"programFiles":["src/modules/webserver.c"],"programRoutines":[{"name":"webserver_handle_request_header()"}],"repo":"https://github.com/unrealircd/unrealircd"}],"references":["https://www.unrealircd.org/","https://forums.unrealircd.org/viewtopic.php?t=9483"],"weaknesses":["CWE-770"],"ingestedAt":"2026-10-29T20:13:34.582Z","source":{"repository":"CVEProject/cvelistV5","path":"cves/2026/90xxx/CVE-2026-90668.json","commit":"556c9d3a8cd17e218bb8e452ba7cd619a384ff47"},"raw":{"dataType":"CVE_RECORD","dataVersion":"5.2","cveMetadata":{"cveId":"CVE-2026-90668","state":"PUBLISHED","datePublished":"2026-09-13T02:00:54.190Z","dateUpdated":"2026-09-14T18:13:44.948Z","assignerShortName":"mitre","assignerOrgId":"8254265b-2729-46b6-b9e3-3dfca2d5bfca","dateReserved":"2026-09-13T02:00:53.718Z"},"containers":{"cna":{"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)."}],"affected":[{"vendor":"UnrealIRCd","product":"UnrealIRCd","defaultStatus":"unaffected","versions":[{"version":"6.0.5","status":"affected","lessThan":"6.2.7","versionType":"semver"}],"modules":["webserver"],"programFiles":["src/modules/webserver.c"],"programRoutines":[{"name":"webserver_handle_request_header()"}],"repo":"https://github.com/unrealircd/unrealircd"}],"references":[{"url":"https://www.unrealircd.org/"},{"url":"https://forums.unrealircd.org/viewtopic.php?t=9483"}],"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":{"shortName":"mitre","orgId":"8254265b-2729-46b6-b9e3-3dfca2d5bfca","dateUpdated":"2026-09-13T02:00:54.190Z"},"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)."}],"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"}]}]}]},"adp":[{"title":"CISA ADP Vulnrichment","metrics":[{"other":{"type":"ssvc","content":{"timestamp":"2026-09-14T18:13:05.650571Z","id":"CVE-2026-90668","options":[{"Exploitation":"none"},{"Automatable":"yes"},{"Technical Impact":"partial"}],"role":"CISA Coordinator","version":"2.0.3"}}}],"providerMetadata":{"shortName":"CISA-ADP","orgId":"134c704f-9b21-4f2e-91b3-4a467353bcc0","dateUpdated":"2026-09-14T18:13:44.948Z"}}]}}}