CVE-2026-32688 (GCVE-0-2026-32688)

Vulnerability from cvelistv5 – Published: 2026-04-27 13:45 – Updated: 2026-04-29 17:08
VLAI?
Title
Atom table exhaustion via HTTP/2 :scheme pseudo-header in plug_cowboy
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 not affect HTTP/1.1, where cowboy derives the scheme from the listener type rather than from a client-supplied header. This issue affects plug_cowboy: from 2.0.0 before 2.8.1.
CWE
  • CWE-770 - Allocation of Resources Without Limits or Throttling
Assigner
EEF
Impacted products
Vendor Product Version
elixir-plug plug_cowboy Affected: 2.0.0 , < 2.8.1 (semver)
    cpe:2.3:a:elixir-plug:plug_cowboy:*:*:*:*:*:*:*:*
Create a notification for this product.
    elixir-plug plug_cowboy Affected: 12ecfd024bb179d48b018fecf074e43fe6a19c83 , < bfb34cb45eb354e56437f7023fb306de1bf9c19b (git)
    cpe:2.3:a:elixir-plug:plug_cowboy:*:*:*:*:*:*:*:*
Create a notification for this product.
Credits
Peter Ullrich
Show details on NVD website

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  }
}


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Tags
Taxonomy of the tags.


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Forecast uses a logistic model when the trend is rising, or an exponential decay model when the trend is falling. Fitted via linearized least squares.

Sightings

Author Source Type Date Other

Nomenclature

  • Seen: The vulnerability was mentioned, discussed, or observed by the user.
  • Confirmed: The vulnerability has been validated from an analyst's perspective.
  • Published Proof of Concept: A public proof of concept is available for this vulnerability.
  • Exploited: The vulnerability was observed as exploited by the user who reported the sighting.
  • Patched: The vulnerability was observed as successfully patched by the user who reported the sighting.
  • Not exploited: The vulnerability was not observed as exploited by the user who reported the sighting.
  • Not confirmed: The user expressed doubt about the validity of the vulnerability.
  • Not patched: The vulnerability was not observed as successfully patched by the user who reported the sighting.


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Detection rules are retrieved from Rulezet.

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