CVE-2026-47077

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.

Weakness classification

• CWE-400: Uncontrolled Resource Consumption

Primary references

• 6b3ad84c-e1a6-4bf7-a703-f496b71e49db — Patch, Third Party Advisory
• 6b3ad84c-e1a6-4bf7-a703-f496b71e49db — Patch
• 6b3ad84c-e1a6-4bf7-a703-f496b71e49db — Exploit, Patch, Vendor Advisory
• 6b3ad84c-e1a6-4bf7-a703-f496b71e49db — Patch, Third Party Advisory
• 134c704f-9b21-4f2e-91b3-4a467353bcc0 — Exploit, Patch, Vendor Advisory