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.

This issue affects hackney: from 2.0.0 before 4.0.1.

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Mon, 25 May 2026 14:30:00 +0000

Type Values Removed Values Added
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. This issue affects hackney: from 2.0.0 before 4.0.1.
Title Unbounded body accumulation in HTTP/3 response loop in hackney
First Time appeared Benoitc
Benoitc hackney
Weaknesses CWE-400
CPEs cpe:2.3:a:benoitc:hackney:*:*:*:*:*:*:*:*
Vendors & Products Benoitc
Benoitc hackney
References
Metrics cvssV4_0

{'score': 8.2, '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'}


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cve-icon MITRE

Status: PUBLISHED

Assigner: EEF

Published:

Updated: 2026-05-25T14:00:42.217Z

Reserved: 2026-05-18T17:28:10.319Z

Link: CVE-2026-47077

cve-icon Vulnrichment

No data.

cve-icon NVD

No data.

cve-icon Redhat

No data.

cve-icon OpenCVE Enrichment

Updated: 2026-05-25T15:45:16Z

Weaknesses