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CVE-2026-32688
HIGH · CVSS 7.5
EPSS exploitation probability: 0%
Published 2026-04-27T14:16:47.340 · Last modified 2026-06-17T10:36:12.470

Summary

Allocation of Resources Without Limits or Throttling vulnerability in elixir-plug plug_cowboy allows unauthenticated remote denial of service via atom table exhaustion. Plug.Cowboy.Conn.conn/1 in lib/plug/cowboy/conn.ex calls String.to_atom/1 on the value returned by :cowboy_req.scheme/1. For HTTP/2 connections, cowlib passes the client-supplied :scheme pseudo-header value through verbatim without validation. Each unique value permanently allocates a new entry in the BEAM atom table. Since atoms are never garbage-collected and the atom table has a fixed limit (default 1,048,576), an unauthenticated attacker can exhaust the table by sending HTTP/2 requests with unique :scheme values, causing the Erlang VM to abort with system_limit and taking down the entire node. This vulnerability does

Affected products

elixir-plug — plug.cowboy

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References

This product uses data from the NVD API but is not endorsed or certified by the NVD. Informational only; not professional security advice.