{"id":"CVE-2026-56853","state":"PUBLISHED","title":"Apply ReadHeaderTimeout when doing unencrypted HTTP/2 check in net/http","description":"When a server is configured to support unencrypted HTTP/2, it reads a few bytes from each new connection to see if they contain the HTTP/2 client preface. ReadHeaderTimeout is unexpectedly not being applied when doing this.","publishedAt":"2026-08-13T21:58:53.092Z","updatedAt":"2026-08-14T15:23:18.680Z","severity":{"score":7.5,"label":"High","version":"3.1","vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H","source":"CISA-ADP"},"assigner":"Go","products":["Go standard library net/http"],"affected":[{"vendor":"Go standard library","product":"net/http","packageName":"net/http","defaultStatus":"unaffected","versions":[{"version":"0","status":"affected","lessThan":"1.25.13","versionType":"semver"},{"version":"1.26.0-0","status":"affected","lessThan":"1.26.6","versionType":"semver"},{"version":"1.27.0-0","status":"affected","lessThan":"1.27.0-rc.3","versionType":"semver"}],"collectionURL":"https://pkg.go.dev","programRoutines":[{"name":"conn.readRequest"},{"name":"conn.serve"},{"name":"ListenAndServe"},{"name":"ListenAndServeTLS"},{"name":"Serve"},{"name":"ServeTLS"},{"name":"Server.ListenAndServe"},{"name":"Server.ListenAndServeTLS"},{"name":"Server.Serve"},{"name":"Server.ServeTLS"}]}],"references":["https://go.dev/issue/80205","https://go.dev/cl/795540","https://groups.google.com/g/golang-announce/c/94pEornpRlI","https://pkg.go.dev/vuln/GO-2026-6089"],"weaknesses":["CWE-770"],"ingestedAt":"2026-10-29T20:12:24.861Z","source":{"repository":"CVEProject/cvelistV5","path":"cves/2026/56xxx/CVE-2026-56853.json","commit":"556c9d3a8cd17e218bb8e452ba7cd619a384ff47"},"raw":{"dataType":"CVE_RECORD","dataVersion":"5.2","cveMetadata":{"cveId":"CVE-2026-56853","state":"PUBLISHED","datePublished":"2026-08-13T21:58:53.092Z","dateUpdated":"2026-08-14T15:23:18.680Z","assignerShortName":"Go","assignerOrgId":"1bb62c36-49e3-4200-9d77-64a1400537cc","dateReserved":"2026-06-23T15:10:49.352Z"},"containers":{"cna":{"title":"Apply ReadHeaderTimeout when doing unencrypted HTTP/2 check in net/http","descriptions":[{"lang":"en","value":"When a server is configured to support unencrypted HTTP/2, it reads a few bytes from each new connection to see if they contain the HTTP/2 client preface. ReadHeaderTimeout is unexpectedly not being applied when doing this."}],"affected":[{"vendor":"Go standard library","product":"net/http","packageName":"net/http","defaultStatus":"unaffected","versions":[{"version":"0","status":"affected","lessThan":"1.25.13","versionType":"semver"},{"version":"1.26.0-0","status":"affected","lessThan":"1.26.6","versionType":"semver"},{"version":"1.27.0-0","status":"affected","lessThan":"1.27.0-rc.3","versionType":"semver"}],"collectionURL":"https://pkg.go.dev","programRoutines":[{"name":"conn.readRequest"},{"name":"conn.serve"},{"name":"ListenAndServe"},{"name":"ListenAndServeTLS"},{"name":"Serve"},{"name":"ServeTLS"},{"name":"Server.ListenAndServe"},{"name":"Server.ListenAndServeTLS"},{"name":"Server.Serve"},{"name":"Server.ServeTLS"}]}],"references":[{"url":"https://go.dev/issue/80205"},{"url":"https://go.dev/cl/795540"},{"url":"https://groups.google.com/g/golang-announce/c/94pEornpRlI"},{"url":"https://pkg.go.dev/vuln/GO-2026-6089"}],"problemTypes":[{"descriptions":[{"lang":"en","description":"CWE-770: Allocation of Resources Without Limits or Throttling"}]}],"providerMetadata":{"shortName":"Go","orgId":"1bb62c36-49e3-4200-9d77-64a1400537cc","dateUpdated":"2026-08-13T21:58:53.092Z"}},"adp":[{"title":"CISA ADP Vulnrichment","metrics":[{"cvssV3_1":{"scope":"UNCHANGED","version":"3.1","baseScore":7.5,"attackVector":"NETWORK","baseSeverity":"HIGH","vectorString":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H","integrityImpact":"NONE","userInteraction":"NONE","attackComplexity":"LOW","availabilityImpact":"HIGH","privilegesRequired":"NONE","confidentialityImpact":"NONE"}},{"other":{"type":"ssvc","content":{"timestamp":"2026-08-14T15:22:45.475320Z","id":"CVE-2026-56853","options":[{"Exploitation":"none"},{"Automatable":"yes"},{"Technical Impact":"partial"}],"role":"CISA Coordinator","version":"2.0.3"}}}],"problemTypes":[{"descriptions":[{"cweId":"CWE-770","type":"CWE","lang":"en","description":"CWE-770 Allocation of Resources Without Limits or Throttling"}]}],"providerMetadata":{"shortName":"CISA-ADP","orgId":"134c704f-9b21-4f2e-91b3-4a467353bcc0","dateUpdated":"2026-08-14T15:23:18.680Z"}}]}}}