CVE-2026-47077 — Unbounded body accumulation in HTTP/3 response loop in hackney
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 m…
Published: 2026-05-25 · CVSS: 8.2 · CVSS 4.0
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.
Source: CVE Program · Revision 8b16575c39f1e1810c5e863010da073d2d3285e7