CVE-2026-39803
Gravedad CVSS v4.0:
ALTA
Tipo:
No Disponible / Otro tipo
Fecha de publicación:
13/05/2026
Última modificación:
13/05/2026
Descripción
*** Pendiente de traducción *** Allocation of Resources Without Limits or Throttling vulnerability in mtrudel bandit allows unauthenticated remote denial of service via memory exhaustion.<br />
<br />
The chunked clause of &#39;Elixir.Bandit.HTTP1.Socket&#39;:read_data/2 in lib/bandit/http1/socket.ex ignores the caller-supplied :length option when reading HTTP/1 chunked request bodies. Instead of capping the accumulated body at the configured limit (e.g. Plug.Parsers&#39; default 8 MB), do_read_chunked_data!/5 buffers every received chunk into an iolist unconditionally and materializes the entire body as a single binary. The function always returns {:ok, body, ...}, so callers cannot interpose a 413 response.<br />
<br />
Because Plug.Parsers runs before routing and authentication in the standard Phoenix endpoint, an unauthenticated attacker needs no valid route or credentials. Sending a single Transfer-Encoding: chunked POST request with an arbitrarily large body to any path causes the BEAM process to exhaust available memory and be terminated by the OS OOM killer.<br />
<br />
The content-length path in the same function correctly enforces the limit and is not affected.<br />
<br />
This issue affects bandit: from 1.4.0 before 1.11.1.
Impacto
Puntuación base 4.0
8.70
Gravedad 4.0
ALTA
Referencias a soluciones, herramientas e información
- https://cna.erlef.org/cves/CVE-2026-39803.html
- https://github.com/mtrudel/bandit/commit/ae3520dfdbfab115c638f8c7f6f6b805db34e1ab
- https://github.com/mtrudel/bandit/security/advisories/GHSA-9q9q-324x-93r2
- https://osv.dev/vulnerability/EEF-CVE-2026-39803
- https://github.com/mtrudel/bandit/security/advisories/GHSA-9q9q-324x-93r2