CVE-2026-32688Network attack vector

Erlang VM crash via HTTP/2 atom exhaustion

Published Apr 27, 2026 · Updated Apr 27, 2026

Resource exhaustion in elixir-plug Plug.Cowboy 2.0.0 through 2.8.0 allows remote attackers to crash the Erlang VM via HTTP/2 requests. Plug.Cowboy.Conn.conn/1 converts each client-supplied :scheme value with String.to_atom/1, permanently consuming a finite BEAM atom-table entry. The endpoint must expose Plug.Cowboy over HTTP/2; HTTP/1.1 derives the scheme internally, while exhaustion aborts the entire node.

CVSS severity8.7
High
EPSS probability0.55%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Resource exhaustion in elixir-plug Plug.Cowboy 2.0.0 through 2.8.0 allows remote attackers to crash the Erlang VM via HTTP/2 requests. Plug.Cowboy.Conn.conn/1 converts each client-supplied :scheme value with String.to_atom/1, permanently consuming a finite BEAM atom-table entry. The endpoint must expose Plug.Cowboy over HTTP/2; HTTP/1.1 derives the scheme internally, while exhaustion aborts the entire node.

The record

CVE
CVE-2026-32688
Published
Apr 27, 2026
Updated
Apr 27, 2026
Vendor
elixir-plug
Product
Plug.Cowboy
Classifications
CWE-770, CAPEC-125, T1499.003
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Apr 27, 2026CVE publishedPublication date reported by the CVE source.
  2. Apr 27, 2026Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=12ecfd024bb179d48b018fecf074e43fe6a19c83 <bfb34cb45eb354e56437f7023fb306de1bf9c19b
  2. Affected versionversion=2.0.0 <2.8.1

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

elixir-plug · Plug.Cowboyversion=12ecfd024bb179d48b018fecf074e43fe6a19c83 <bfb34cb45eb354e56437f7023fb306de1bf9c19b; version=2.0.0 <2.8.1

Published CVSS scores

7.5NIST NVDCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
8.7Erlang Ecosystem FoundationCVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

Daily unique IPsNo honeypot observations are available for this CVE in the selected window.

No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-770Allocation of Resources Without Limits or Throttling
CAPEC-125Flooding
T1499.003Endpoint Denial of Service: Application Exhaustion Flood

Public exploit references

No public exploit references are available in this record.

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

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Your stack

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