CVE-2026-54274Network attack vector

Unauthenticated service interruption via late WebSocket size enforcement

Published Jun 22, 2026 · Updated Jun 22, 2026

Resource exhaustion in aiohttp before 3.14.1 allows remote attackers to interrupt WebSocket services with oversized incomplete frames. WebSocketReader enforces max_msg_size only after assembling payload data, so an incomplete frame can consume memory before the size check runs. A reachable aiohttp WebSocket endpoint is required; sustained memory growth can exhaust the hosting process and interrupt its service.

CVSS severity7.5
High
EPSS probability0.30%
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 aiohttp before 3.14.1 allows remote attackers to interrupt WebSocket services with oversized incomplete frames. WebSocketReader enforces max_msg_size only after assembling payload data, so an incomplete frame can consume memory before the size check runs. A reachable aiohttp WebSocket endpoint is required; sustained memory growth can exhaust the hosting process and interrupt its service.

The record

CVE
CVE-2026-54274
Published
Jun 22, 2026
Updated
Jun 22, 2026
Vendor
aio-libs
Product
aiohttp
Classifications
CWE-770, T1499.003
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Jun 22, 2026CVE publishedPublication date reported by the CVE source.
  2. Jun 22, 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=< 3.14.1

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

aio-libs · aiohttpversion=< 3.14.1

Published CVSS scores

7.5NIST NVDCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
6.6GitHubCVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N/E:U

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 9, 2026Sep 15, 2026
Latest reporting daySep 15, 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
T1499.003Application Exhaustion

Public exploit references

No public exploit references are available in this record.

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Technologies

Your stack

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Your stack

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