{"id":"EEF-CVE-2026-47077","summary":"Unbounded body accumulation in HTTP/3 response loop in hackney","details":"## Summary\n\nAllocation 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.\n\n## Configuration\n\nThe 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.","aliases":["CVE-2026-47077","GHSA-jq4m-q6p2-8gwc"],"modified":"2026-05-27T16:00:13.987384010Z","published":"2026-05-25T14:00:42.217Z","database_specific":{"cwe_ids":["CWE-400"],"cpe_ids":["cpe:2.3:a:benoitc:hackney:*:*:*:*:*:*:*:*"],"capec_ids":["CAPEC-125"]},"references":[{"type":"ADVISORY","url":"https://github.com/benoitc/hackney/security/advisories/GHSA-jq4m-q6p2-8gwc"},{"type":"WEB","url":"https://cna.erlef.org/cves/CVE-2026-47077.html"},{"type":"FIX","url":"https://github.com/benoitc/hackney/commit/3d25f9fea26c90609de9d64366fedfe5065413bc"},{"type":"PACKAGE","url":"https://hex.pm/packages/hackney"}],"affected":[{"package":{"name":"hackney","ecosystem":"Hex","purl":"pkg:hex/hackney"},"ranges":[{"type":"SEMVER","events":[{"introduced":"2.0.0"},{"fixed":"4.0.1"}]}],"versions":["2.0.0","2.0.1","3.0.0","3.0.1","3.0.2","3.0.3","3.1.0","3.1.1","3.1.2","3.2.0","3.2.1","4.0.0"],"database_specific":{"source":"https://cna.erlef.org/osv/EEF-CVE-2026-47077.json"}},{"ranges":[{"type":"GIT","repo":"https://github.com/benoitc/hackney","events":[{"introduced":"0334af206d5099fdf510ed9eda18e34396f065ad"},{"fixed":"3d25f9fea26c90609de9d64366fedfe5065413bc"}]}],"database_specific":{"source":"https://cna.erlef.org/osv/EEF-CVE-2026-47077.json"}}],"schema_version":"1.7.5","severity":[{"type":"CVSS_V4","score":"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"}],"credits":[{"name":"Peter Ullrich","type":"FINDER"},{"name":"Benoit Chesneau","type":"REMEDIATION_DEVELOPER"},{"name":"Jonatan Männchen / EEF","type":"ANALYST"}]}