{"id":"CVE-2026-47077","state":"PUBLISHED","title":"Unbounded body accumulation in HTTP/3 response loop in hackney","description":"Allocation of Resources Without Limits or Throttling vulnerability in benoitc hackney allows Flooding. hackney_h3:await_response_loop/6 accumulates the HTTP/3 response body in memory without any size cap. The after Timeout clause is a per-message inactivity timer that resets on every received chunk, housekeeping message, or settings frame — it is not a wall-clock deadline. A malicious HTTP/3 server that emits one small chunk every Timeout - 1 ms with Fin = false and never sends a final frame keeps the loop alive indefinitely while the accumulation buffer grows linearly without bound, eventually exhausting the BEAM process heap and causing an out-of-memory condition.\n\nThis issue affects hackney: from 2.0.0 before 4.0.1.","publishedAt":"2026-05-25T14:00:42.217Z","updatedAt":"2026-05-27T15:40:53.384Z","severity":{"score":8.2,"label":"High","version":"4.0","vector":"CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N","source":"EEF"},"assigner":"EEF","products":["benoitc hackney"],"affected":[{"vendor":"benoitc","product":"hackney","packageName":"hackney","packageURL":"pkg:hex/hackney","defaultStatus":"unaffected","versions":[{"version":"2.0.0","status":"affected","lessThan":"4.0.1","versionType":"semver"}],"collectionURL":"https://repo.hex.pm","cpes":["cpe:2.3:a:benoitc:hackney:*:*:*:*:*:*:*:*"],"modules":["hackney_h3"],"programFiles":["src/hackney_h3.erl"],"programRoutines":[{"name":"hackney_h3:await_response_loop/6"}],"repo":"https://github.com/benoitc/hackney"},{"vendor":"benoitc","product":"hackney","packageName":"benoitc/hackney","packageURL":"pkg:github/benoitc/hackney","defaultStatus":"unaffected","versions":[{"version":"0334af206d5099fdf510ed9eda18e34396f065ad","status":"affected","lessThan":"3d25f9fea26c90609de9d64366fedfe5065413bc","versionType":"git"}],"collectionURL":"https://github.com","cpes":["cpe:2.3:a:benoitc:hackney:*:*:*:*:*:*:*:*"],"modules":["hackney_h3"],"programFiles":["src/hackney_h3.erl"],"programRoutines":[{"name":"hackney_h3:await_response_loop/6"}],"repo":"https://github.com/benoitc/hackney"}],"references":["https://github.com/benoitc/hackney/security/advisories/GHSA-jq4m-q6p2-8gwc","https://cna.erlef.org/cves/CVE-2026-47077.html","https://osv.dev/vulnerability/EEF-CVE-2026-47077","https://github.com/benoitc/hackney/commit/3d25f9fea26c90609de9d64366fedfe5065413bc"],"weaknesses":["CWE-400"],"ingestedAt":"2026-10-29T20:12:07.131Z","source":{"repository":"CVEProject/cvelistV5","path":"cves/2026/47xxx/CVE-2026-47077.json","commit":"556c9d3a8cd17e218bb8e452ba7cd619a384ff47"},"raw":{"dataType":"CVE_RECORD","dataVersion":"5.2","cveMetadata":{"cveId":"CVE-2026-47077","state":"PUBLISHED","datePublished":"2026-05-25T14:00:42.217Z","dateUpdated":"2026-05-27T15:40:53.384Z","assignerShortName":"EEF","assignerOrgId":"6b3ad84c-e1a6-4bf7-a703-f496b71e49db","dateReserved":"2026-05-18T17:28:10.319Z"},"containers":{"cna":{"title":"Unbounded body accumulation in HTTP/3 response loop in hackney","descriptions":[{"lang":"en","value":"Allocation of Resources Without Limits or Throttling vulnerability in benoitc hackney allows Flooding. hackney_h3:await_response_loop/6 accumulates the HTTP/3 response body in memory without any size cap. The after Timeout clause is a per-message inactivity timer that resets on every received chunk, housekeeping message, or settings frame — it is not a wall-clock deadline. A malicious HTTP/3 server that emits one small chunk every Timeout - 1 ms with Fin = false and never sends a final frame keeps the loop alive indefinitely while the accumulation buffer grows linearly without bound, eventually exhausting the BEAM process heap and causing an out-of-memory condition.\n\nThis issue affects hackney: from 2.0.0 before 4.0.1."}],"affected":[{"vendor":"benoitc","product":"hackney","packageName":"hackney","packageURL":"pkg:hex/hackney","defaultStatus":"unaffected","versions":[{"version":"2.0.0","status":"affected","lessThan":"4.0.1","versionType":"semver"}],"collectionURL":"https://repo.hex.pm","cpes":["cpe:2.3:a:benoitc:hackney:*:*:*:*:*:*:*:*"],"modules":["hackney_h3"],"programFiles":["src/hackney_h3.erl"],"programRoutines":[{"name":"hackney_h3:await_response_loop/6"}],"repo":"https://github.com/benoitc/hackney"},{"vendor":"benoitc","product":"hackney","packageName":"benoitc/hackney","packageURL":"pkg:github/benoitc/hackney","defaultStatus":"unaffected","versions":[{"version":"0334af206d5099fdf510ed9eda18e34396f065ad","status":"affected","lessThan":"3d25f9fea26c90609de9d64366fedfe5065413bc","versionType":"git"}],"collectionURL":"https://github.com","cpes":["cpe:2.3:a:benoitc:hackney:*:*:*:*:*:*:*:*"],"modules":["hackney_h3"],"programFiles":["src/hackney_h3.erl"],"programRoutines":[{"name":"hackney_h3:await_response_loop/6"}],"repo":"https://github.com/benoitc/hackney"}],"references":[{"url":"https://github.com/benoitc/hackney/security/advisories/GHSA-jq4m-q6p2-8gwc","tags":["vendor-advisory","related"]},{"url":"https://cna.erlef.org/cves/CVE-2026-47077.html","tags":["related"]},{"url":"https://osv.dev/vulnerability/EEF-CVE-2026-47077","tags":["related"]},{"url":"https://github.com/benoitc/hackney/commit/3d25f9fea26c90609de9d64366fedfe5065413bc","tags":["patch"]}],"metrics":[{"cvssV4_0":{"attackComplexity":"LOW","attackRequirements":"PRESENT","attackVector":"NETWORK","baseScore":8.2,"baseSeverity":"HIGH","privilegesRequired":"NONE","subAvailabilityImpact":"NONE","subConfidentialityImpact":"NONE","subIntegrityImpact":"NONE","userInteraction":"NONE","vectorString":"CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N","version":"4.0","vulnAvailabilityImpact":"HIGH","vulnConfidentialityImpact":"NONE","vulnIntegrityImpact":"NONE"},"format":"CVSS","scenarios":[{"lang":"en","value":"GENERAL"}]}],"problemTypes":[{"descriptions":[{"cweId":"CWE-400","description":"CWE-400 Uncontrolled Resource Consumption","lang":"en","type":"CWE"}]}],"providerMetadata":{"shortName":"EEF","orgId":"6b3ad84c-e1a6-4bf7-a703-f496b71e49db","dateUpdated":"2026-05-27T15:40:53.384Z"},"configurations":[{"lang":"en","supportingMedia":[{"base64":false,"type":"text/html","value":"The application must use the HTTP/3 transport by calling <tt>hackney_h3</tt> directly or by passing <tt>{transport, h3}</tt> to <tt>hackney:request/5</tt>. The default hackney transport (TCP/TLS) is not affected."}],"value":"The application must use the HTTP/3 transport by calling hackney_h3 directly or by passing {transport, h3} to hackney:request/5. The default hackney transport (TCP/TLS) is not affected."}],"cpeApplicability":[{"nodes":[{"cpeMatch":[{"criteria":"cpe:2.3:a:benoitc:hackney:*:*:*:*:*:*:*:*","versionEndExcluding":"4.0.1","versionStartIncluding":"2.0.0","vulnerable":true}],"negate":false,"operator":"AND"}],"operator":"AND"}],"credits":[{"lang":"en","type":"finder","value":"Peter Ullrich"},{"lang":"en","type":"remediation developer","value":"Benoit Chesneau"},{"lang":"en","type":"analyst","value":"Jonatan Männchen / EEF"}],"impacts":[{"capecId":"CAPEC-125","descriptions":[{"lang":"en","value":"CAPEC-125 Flooding"}]}],"source":{"discovery":"EXTERNAL"},"x_generator":{"engine":"cvelib 1.8.0"}},"adp":[{"title":"CISA ADP Vulnrichment","references":[{"url":"https://github.com/benoitc/hackney/security/advisories/GHSA-jq4m-q6p2-8gwc","tags":["exploit"]}],"metrics":[{"other":{"type":"ssvc","content":{"timestamp":"2026-05-26T15:47:51.427632Z","id":"CVE-2026-47077","options":[{"Exploitation":"poc"},{"Automatable":"yes"},{"Technical Impact":"partial"}],"role":"CISA Coordinator","version":"2.0.3"}}}],"providerMetadata":{"shortName":"CISA-ADP","orgId":"134c704f-9b21-4f2e-91b3-4a467353bcc0","dateUpdated":"2026-05-26T15:47:54.752Z"}}]}}}