CVE-2026-54274: aiohttp Incomplete Websocket Frame Payloads Bypass Vulnerability

MODERATE
Advisory Identifier: GHSA-xcgm-r5h9-7989
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CWE-770
Published
Advisory Summary

CVE-2026-54274 is a MODERATE incomplete websocket frame payloads bypass vulnerability (CWE-770: Allocation of Resources Without Limits or Throttling) affecting aiohttp libraries in the PyPI ecosystem. The issue involves incomplete websocket frame payloads bypass memory limits. Remediation is available by upgrading affected packages to version 3.14.1.

CVE-2026-54274 at a Glance

CVE Identifier CVE-2026-54274
GHSA Identifier GHSA-xcgm-r5h9-7989
Severity MODERATE
CVSS v3.1 Base Score N/A
CWE Classification CWE-770: Allocation of Resources Without Limits or Throttling
Affected Product aiohttp
Package Ecosystem PyPI
Published Date
Last Updated

How to Fix CVE-2026-54274

To remediate this vulnerability, upgrade all affected aiohttp dependencies to a patched release. Both direct and transitive dependencies should be checked, as frameworks or security libraries may pull in vulnerable versions transitively.

aiohttp fixed: 3.14.1 
pip install aiohttp>=3.14.1
Verify Direct and Transitive Dependencies

Run the following command in your project directory to verify that all resolved dependencies use the patched release: 

pip show aiohttp

How to Check if You Are Affected

To determine whether your Python environment is affected by CVE-2026-54274, inspect your installed packages using pip:

pip show aiohttp

Analyze the terminal output to locate any version of aiohttp in your dependency tree. If any resolved version matches the vulnerable ranges listed in the table below (for example, versions earlier than 3.14.1), your application is affected.

Note: The pip show aiohttp command checks currently installed packages in your active Python environment.

Technical Details

Vulnerability Mechanism & Technical Analysis

This vulnerability is classified under CWE-770: Allocation of Resources Without Limits or Throttling, where the product allocates a reusable resource or group of resources on behalf of an actor without imposing any intended restrictions on the size or number of resources that can be allocated. In aiohttp, software state validation or input boundaries are circumvented during processing. Review the official source advisory statement below for specific affected components, classes, and reproduction details.

Source Advisory Statement

### Summary If an attacker sends large incomplete websocket frame payloads, it may be possible to bypass the usual size limits on memory use. ### Impact If a web application has WebSocket endpoints, it may be possible for an attacker to execute a DoS attack through excessive memory use. ----- Patch: https://github.com/aio-libs/aiohttp/commit/14b6ee851fb16ec199acb950de0c82d476799e7d

CVE-2026-54274 Affected aiohttp Versions

1 component(s)
Fixed Versions:
3.14.1
Product / Package Ecosystem Affected Versions Fixed Version
aiohttp
pypi/aiohttp
PyPI
< 3.14.1
3.14.1

References

GitHub Advisory / Wiki ADVISORY
https://github.com/aio-libs/aiohttp/security/advisories/GHSA-xcgm-r5h9-7989
aiohttp Source Repository REPOSITORY
https://github.com/aio-libs/aiohttp

Frequently Asked Questions

What is CVE-2026-54274?
CVE-2026-54274 is a security vulnerability in aiohttp involving Incomplete websocket frame payloads bypass memory limits under CWE-770: Allocation of Resources Without Limits or Throttling.
Which aiohttp versions are affected?
Affected versions include releases prior to 3.14.1 across affected packages: aiohttp.
What version fixes CVE-2026-54274?
Upgrading to 3.14.1 (or the latest patched release for your respective branch) resolves the vulnerability.
Is aiohttp affected?
Yes, aiohttp is affected in releases prior to 3.14.1. Upgrade your dependency to 3.14.1 or later.
What CWE is associated with CVE-2026-54274?
CVE-2026-54274 is classified under CWE-770: Allocation of Resources Without Limits or Throttling (The product allocates a reusable resource or group of resources on behalf of an actor without imposing any intended restrictions on the size or number of resources that can be allocated.).
How can I check PyPI dependencies for CVE-2026-54274?
Run the dependency tree command: 'pip show aiohttp'. This command lists direct and transitive dependencies in your build configuration so you can verify if a vulnerable version is resolved.
Machine-readable OSV JSON OSV v1.5 Schema
Normalized schema output
View Raw JSON 
{
  "schema_version" : "1.4.0",
  "id" : "GHSA-xcgm-r5h9-7989",
  "modified" : "2026-06-15T20:11:22Z",
  "published" : "2026-06-15T20:11:22Z",
  "aliases" : [ "CVE-2026-54274" ],
  "summary" : "aiohttp: Incomplete websocket frame payloads bypass memory limits",
  "details" : "### Summary\n\nIf an attacker sends large incomplete websocket frame payloads, it may be possible to bypass the usual size limits on memory use.\n\n### Impact\n\nIf a web application has WebSocket endpoints, it may be possible for an attacker to execute a DoS attack through excessive memory use.\n\n-----\n\nPatch: https://github.com/aio-libs/aiohttp/commit/14b6ee851fb16ec199acb950de0c82d476799e7d",
  "severity" : [ {
    "type" : "CVSS_V4",
    "score" : "CVSS: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"
  } ],
  "affected" : [ {
    "package" : {
      "ecosystem" : "PyPI",
      "name" : "aiohttp"
    },
    "ranges" : [ {
      "type" : "ECOSYSTEM",
      "events" : [ {
        "introduced" : "0"
      }, {
        "fixed" : "3.14.1"
      } ]
    } ],
    "database_specific" : {
      "last_known_affected_version_range" : "<= 3.14.0"
    }
  } ],
  "references" : [ {
    "type" : "WEB",
    "url" : "https://github.com/aio-libs/aiohttp/security/advisories/GHSA-xcgm-r5h9-7989"
  }, {
    "type" : "PACKAGE",
    "url" : "https://github.com/aio-libs/aiohttp"
  } ],
  "database_specific" : {
    "cwe_ids" : [ "CWE-770" ],
    "severity" : "MODERATE",
    "github_reviewed" : true,
    "github_reviewed_at" : "2026-06-15T20:11:22Z",
    "nvd_published_at" : null
  }
}