CVE-2025-69227: Aiohttp Denial of Service Vulnerability

MODERATE
Advisory Identifier: GHSA-jj3x-wxrx-4x23
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CWE-835
Published
Advisory Summary

CVE-2025-69227 is a MODERATE denial of service vulnerability (CWE-835: Loop with Unreachable Exit Condition ('Infinite Loop')) affecting Aiohttp libraries in the PyPI ecosystem. The issue involves aiohttp vulnerable to dos when bypassing asserts. Remediation is available by upgrading affected packages to version 3.13.3.

CVE-2025-69227 at a Glance

CVE Identifier CVE-2025-69227
GHSA Identifier GHSA-jj3x-wxrx-4x23
Severity MODERATE
CVSS v3.1 Base Score N/A
CWE Classification CWE-835: Loop with Unreachable Exit Condition ('Infinite Loop')
Affected Product Aiohttp
Package Ecosystem PyPI
Published Date
Last Updated

How to Fix CVE-2025-69227

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: 3.13.3 
pip install aiohttp>=3.13.3
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-2025-69227, 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 3.13.3), 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-835: Loop with Unreachable Exit Condition ('Infinite Loop'), where the product contains an iteration or loop with an exit condition that cannot be reached, i.e., an infinite loop. 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 When assert statements are bypassed, an infinite loop can occur, resulting in a DoS attack when processing a POST body. ### Impact If optimisations are enabled (`-O` or `PYTHONOPTIMIZE=1`), and the application includes a handler that uses the `Request.post()` method, then an attacker may be able to execute a DoS attack with a specially crafted message. ------ Patch: https://github.com/aio-libs/aiohttp/commit/bc1319ec3cbff9438a758951a30907b072561259

CVE-2025-69227 Affected Aiohttp Versions

1 component(s)
Fixed Versions:
3.13.3
Product / Package Ecosystem Affected Versions Fixed Version
aiohttp
pypi/aiohttp
PyPI
< 3.13.3
3.13.3

References

GitHub Advisory / Wiki ADVISORY
https://github.com/aio-libs/aiohttp/security/advisories/GHSA-jj3x-wxrx-4x23
NVD — CVE-2025-69227 NVD
https://nvd.nist.gov/vuln/detail/CVE-2025-69227
Security Fix Commit FIX COMMIT
https://github.com/aio-libs/aiohttp/commit/bc1319ec3cbff9438a758951a30907b072561259
Aiohttp Source Repository REPOSITORY
https://github.com/aio-libs/aiohttp

Frequently Asked Questions

What is CVE-2025-69227?
CVE-2025-69227 is a security vulnerability in Aiohttp involving AIOHTTP vulnerable to DoS when bypassing asserts under CWE-835: Loop with Unreachable Exit Condition ('Infinite Loop').
Which Aiohttp versions are affected?
Affected versions include releases prior to 3.13.3 across affected packages: aiohttp.
What version fixes CVE-2025-69227?
Upgrading to 3.13.3 (or the latest patched release for your respective branch) resolves the vulnerability.
Is aiohttp affected?
Yes, aiohttp is affected in releases prior to 3.13.3. Upgrade your dependency to 3.13.3 or later.
What CWE is associated with CVE-2025-69227?
CVE-2025-69227 is classified under CWE-835: Loop with Unreachable Exit Condition ('Infinite Loop') (The product contains an iteration or loop with an exit condition that cannot be reached, i.e., an infinite loop.).
How can I check PyPI dependencies for CVE-2025-69227?
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-jj3x-wxrx-4x23",
  "modified" : "2026-01-06T16:06:51Z",
  "published" : "2026-01-05T23:10:15Z",
  "aliases" : [ "CVE-2025-69227" ],
  "summary" : "AIOHTTP vulnerable to DoS when bypassing asserts",
  "details" : "### Summary\nWhen assert statements are bypassed, an infinite loop can occur, resulting in a DoS attack when processing a POST body.\n\n### Impact\nIf optimisations are enabled (`-O` or `PYTHONOPTIMIZE=1`), and the application includes a handler that uses the `Request.post()` method, then an attacker may be able to execute a DoS attack with a specially crafted message.\n\n------\n\nPatch: https://github.com/aio-libs/aiohttp/commit/bc1319ec3cbff9438a758951a30907b072561259",
  "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" : "3.13.3"
      } ]
    } ],
    "database_specific" : {
      "last_known_affected_version_range" : "<= 3.13.2"
    }
  } ],
  "references" : [ {
    "type" : "WEB",
    "url" : "https://github.com/aio-libs/aiohttp/security/advisories/GHSA-jj3x-wxrx-4x23"
  }, {
    "type" : "ADVISORY",
    "url" : "https://nvd.nist.gov/vuln/detail/CVE-2025-69227"
  }, {
    "type" : "WEB",
    "url" : "https://github.com/aio-libs/aiohttp/commit/bc1319ec3cbff9438a758951a30907b072561259"
  }, {
    "type" : "PACKAGE",
    "url" : "https://github.com/aio-libs/aiohttp"
  } ],
  "database_specific" : {
    "cwe_ids" : [ "CWE-835" ],
    "severity" : "MODERATE",
    "github_reviewed" : true,
    "github_reviewed_at" : "2026-01-05T23:10:15Z",
    "nvd_published_at" : "2026-01-06T00:15:48Z"
  }
}