CVE-2026-32688

  1. OpenCVE
  2. Vulnerabilities (CVE)
  3. CVE-2026-32688
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.

7.5 /10

CVSS v3 : HIGH

V3 Legend

Vector :

Exploitability : 3.9 / Impact : 3.6

Attack Vector NETWORK

Attack Complexity LOW

Privileges Required NONE

User Interaction NONE

Confidentiality Impact NONE

Integrity Impact NONE

Availability Impact HIGH

Scope UNCHANGED

References
Link Resource
https://cna.erlef.org/cves/CVE-2026-32688.html Third Party Advisory
https://github.com/elixir-plug/plug_cowboy/commit/bfb34cb45eb354e56437f7023fb306de1bf9c19b Patch
https://github.com/elixir-plug/plug_cowboy/security/advisories/GHSA-q8x4-x7mp-5vg2 Vendor Advisory
https://osv.dev/vulnerability/EEF-CVE-2026-32688 Third Party Advisory
Configurations

Configuration 1 (hide)

cpe:2.3:a:elixir-plug:plug.cowboy:*:*:*:*:*:*:*:*
History

22 May 2026, 14:05

Type Values Removed Values Added
References () https://cna.erlef.org/cves/CVE-2026-32688.html - () https://cna.erlef.org/cves/CVE-2026-32688.html - Third Party Advisory
References () https://github.com/elixir-plug/plug_cowboy/commit/bfb34cb45eb354e56437f7023fb306de1bf9c19b - () https://github.com/elixir-plug/plug_cowboy/commit/bfb34cb45eb354e56437f7023fb306de1bf9c19b - Patch
References () https://github.com/elixir-plug/plug_cowboy/security/advisories/GHSA-q8x4-x7mp-5vg2 - () https://github.com/elixir-plug/plug_cowboy/security/advisories/GHSA-q8x4-x7mp-5vg2 - Vendor Advisory
References () https://osv.dev/vulnerability/EEF-CVE-2026-32688 - () https://osv.dev/vulnerability/EEF-CVE-2026-32688 - Third Party Advisory
CVSS v2 : unknown
v3 : unknown 		v2 : unknown
v3 : 7.5
CPE cpe:2.3:a:elixir-plug:plug.cowboy:*:*:*:*:*:*:*:*
First Time Elixir-plug
Elixir-plug plug.cowboy

27 Apr 2026, 14:16

Type Values Removed Values Added
New CVE
Information

Published : 2026-04-27 14:16

Updated : 2026-05-22 14:05

NVD link : CVE-2026-32688

Mitre link : CVE-2026-32688

CVE.ORG link : CVE-2026-32688

JSON object : View

Products Affected

elixir-plug

  • plug.cowboy
CWE
CWE-770

Allocation of Resources Without Limits or Throttling