CVE-2025-69225: Aiohttp AIOHTTP Has Unicode Match Groups Vulnerability

LOW
Advisory Identifier: GHSA-mqqc-3gqh-h2x8
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CWE-444
Published
Advisory Summary

CVE-2025-69225 is a LOW aiohttp has unicode match groups vulnerability (CWE-444: Inconsistent Interpretation of HTTP Requests ('HTTP Request/Response Smuggling')) affecting Aiohttp libraries in the PyPI ecosystem. The issue involves aiohttp has unicode match groups in regexes for ascii protocol elements. Remediation is available by upgrading affected packages to version 3.13.3.

CVE-2025-69225 at a Glance

CVE Identifier CVE-2025-69225
GHSA Identifier GHSA-mqqc-3gqh-h2x8
Severity LOW
CVSS v3.1 Base Score N/A
CWE Classification CWE-444: Inconsistent Interpretation of HTTP Requests ('HTTP Request/Response Smuggling')
Affected Product Aiohttp
Package Ecosystem PyPI
Published Date
Last Updated

How to Fix CVE-2025-69225

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-2025-69225, 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-444: Inconsistent Interpretation of HTTP Requests ('HTTP Request/Response Smuggling'), where the product acts as an intermediary http agent (such as a proxy or firewall) in the data flow between two entities such as a client and server, but it does not interpret malformed http requests or responses in ways that are consistent with how the messages will be processed by those entities that are at the ultimate destination. 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 The parser allows non-ASCII decimals to be present in the Range header. ### Impact There is no known impact, but there is the possibility that there's a method to exploit a request smuggling vulnerability. ---- Patch: https://github.com/aio-libs/aiohttp/commit/c7b7a044f88c71cefda95ec75cdcfaa4792b3b96

CVE-2025-69225 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-mqqc-3gqh-h2x8
NVD — CVE-2025-69225 NVD
https://nvd.nist.gov/vuln/detail/CVE-2025-69225
Security Fix Commit FIX COMMIT
https://github.com/aio-libs/aiohttp/commit/c7b7a044f88c71cefda95ec75cdcfaa4792b3b96
Aiohttp Source Repository REPOSITORY
https://github.com/aio-libs/aiohttp

Frequently Asked Questions

What is CVE-2025-69225?
CVE-2025-69225 is a security vulnerability in Aiohttp involving AIOHTTP has unicode match groups in regexes for ASCII protocol elements under CWE-444: Inconsistent Interpretation of HTTP Requests ('HTTP Request/Response Smuggling').
Which Aiohttp versions are affected?
Affected versions include releases prior to 3.13.3 across affected packages: aiohttp.
What version fixes CVE-2025-69225?
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-2025-69225?
CVE-2025-69225 is classified under CWE-444: Inconsistent Interpretation of HTTP Requests ('HTTP Request/Response Smuggling') (The product acts as an intermediary HTTP agent (such as a proxy or firewall) in the data flow between two entities such as a client and server, but it does not interpret malformed HTTP requests or responses in ways that are consistent with how the messages will be processed by those entities that are at the ultimate destination.).
How can I check PyPI dependencies for CVE-2025-69225?
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-mqqc-3gqh-h2x8",
  "modified" : "2026-01-06T16:06:44Z",
  "published" : "2026-01-05T23:09:30Z",
  "aliases" : [ "CVE-2025-69225" ],
  "summary" : "AIOHTTP has unicode match groups in regexes for ASCII protocol elements",
  "details" : "### Summary\n\nThe parser allows non-ASCII decimals to be present in the Range header.\n\n### Impact\n\nThere is no known impact, but there is the possibility that there's a method to exploit a request smuggling vulnerability.\n\n----\n\nPatch: https://github.com/aio-libs/aiohttp/commit/c7b7a044f88c71cefda95ec75cdcfaa4792b3b96",
  "severity" : [ {
    "type" : "CVSS_V4",
    "score" : "CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:L/VA:N/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-mqqc-3gqh-h2x8"
  }, {
    "type" : "ADVISORY",
    "url" : "https://nvd.nist.gov/vuln/detail/CVE-2025-69225"
  }, {
    "type" : "WEB",
    "url" : "https://github.com/aio-libs/aiohttp/commit/c7b7a044f88c71cefda95ec75cdcfaa4792b3b96"
  }, {
    "type" : "PACKAGE",
    "url" : "https://github.com/aio-libs/aiohttp"
  } ],
  "database_specific" : {
    "cwe_ids" : [ "CWE-444" ],
    "severity" : "LOW",
    "github_reviewed" : true,
    "github_reviewed_at" : "2026-01-05T23:09:30Z",
    "nvd_published_at" : "2026-01-06T00:15:47Z"
  }
}