CVE-2026-47265: Aiohttp AIOHTTP Is Vulnerable To Cross-origin Vulnerability

MODERATE
Advisory Identifier: GHSA-hg6j-4rv6-33pg
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CWE-346
Published
Advisory Summary

CVE-2026-47265 is a MODERATE aiohttp is vulnerable to cross-origin vulnerability (CWE-346: Origin Validation Error) affecting Aiohttp libraries in the PyPI ecosystem. The issue involves aiohttp is vulnerable to cross-origin redirect with per-request cookies. Remediation is available by upgrading affected packages to version 3.14.0.

CVE-2026-47265 at a Glance

CVE Identifier CVE-2026-47265
GHSA Identifier GHSA-hg6j-4rv6-33pg
Severity MODERATE
CVSS v3.1 Base Score N/A
CWE Classification CWE-346: Origin Validation Error
Affected Product Aiohttp
Package Ecosystem PyPI
Published Date
Last Updated

How to Fix CVE-2026-47265

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: 3.14.0 
pip install aiohttp>=3.14.0
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-2026-47265, 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 3.14.0), 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-346: Origin Validation Error, where the product does not properly verify that the source of data or communication is valid. 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 Cookies set with the `cookies` parameter on requests are sent after following a cross-origin redirect. ### Impact If a developer uses the `cookies` parameter on a per-request basis then sensitive data might be leaked to an attacker if they manage to control a redirect. ### Workaround If unable to upgrade, using a `Cookie` header in the `headers` parameter is not vulnerable. ----- Patch: https://github.com/aio-libs/aiohttp/commit/f54c40851b0d6c4bbdab97ba518a223adda32478

CVE-2026-47265 Affected Aiohttp Versions

1 component(s)
Fixed Versions:
3.14.0
Product / Package Ecosystem Affected Versions Fixed Version
aiohttp
pypi/aiohttp
PyPI
< 3.14.0
3.14.0

References

GitHub Advisory / Wiki ADVISORY
https://github.com/aio-libs/aiohttp/security/advisories/GHSA-hg6j-4rv6-33pg
NVD — CVE-2026-47265 NVD
https://nvd.nist.gov/vuln/detail/CVE-2026-47265
Security Fix Commit FIX COMMIT
https://github.com/aio-libs/aiohttp/commit/f54c40851b0d6c4bbdab97ba518a223adda32478
Aiohttp Source Repository REPOSITORY
https://github.com/aio-libs/aiohttp

Frequently Asked Questions

What is CVE-2026-47265?
CVE-2026-47265 is a security vulnerability in Aiohttp involving AIOHTTP is vulnerable to cross-origin redirect with per-request cookies under CWE-346: Origin Validation Error.
Which Aiohttp versions are affected?
Affected versions include releases prior to 3.14.0 across affected packages: aiohttp.
What version fixes CVE-2026-47265?
Upgrading to 3.14.0 (or the latest patched release for your respective branch) resolves the vulnerability.
Is aiohttp affected?
Yes, aiohttp is affected in releases prior to 3.14.0. Upgrade your dependency to 3.14.0 or later.
What CWE is associated with CVE-2026-47265?
CVE-2026-47265 is classified under CWE-346: Origin Validation Error (The product does not properly verify that the source of data or communication is valid.).
How can I check PyPI dependencies for CVE-2026-47265?
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-hg6j-4rv6-33pg",
  "modified" : "2026-06-03T21:34:38Z",
  "published" : "2026-06-03T21:34:38Z",
  "aliases" : [ "CVE-2026-47265" ],
  "summary" : "AIOHTTP is vulnerable to cross-origin redirect with per-request cookies",
  "details" : "### Summary\n\nCookies set with the `cookies` parameter on requests are sent after following a cross-origin redirect.\n\n### Impact\n\nIf a developer uses the `cookies` parameter on a per-request basis then sensitive data might be leaked to an attacker if they manage to control a redirect.\n\n### Workaround\n\nIf unable to upgrade, using a `Cookie` header in the `headers` parameter is not vulnerable.\n\n-----\n\nPatch: https://github.com/aio-libs/aiohttp/commit/f54c40851b0d6c4bbdab97ba518a223adda32478",
  "severity" : [ {
    "type" : "CVSS_V4",
    "score" : "CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:N/VA:N/SC:N/SI:N/SA:N/E:U"
  } ],
  "affected" : [ {
    "package" : {
      "ecosystem" : "PyPI",
      "name" : "aiohttp"
    },
    "ranges" : [ {
      "type" : "ECOSYSTEM",
      "events" : [ {
        "introduced" : "0"
      }, {
        "fixed" : "3.14.0"
      } ]
    } ]
  } ],
  "references" : [ {
    "type" : "WEB",
    "url" : "https://github.com/aio-libs/aiohttp/security/advisories/GHSA-hg6j-4rv6-33pg"
  }, {
    "type" : "ADVISORY",
    "url" : "https://nvd.nist.gov/vuln/detail/CVE-2026-47265"
  }, {
    "type" : "WEB",
    "url" : "https://github.com/aio-libs/aiohttp/commit/f54c40851b0d6c4bbdab97ba518a223adda32478"
  }, {
    "type" : "PACKAGE",
    "url" : "https://github.com/aio-libs/aiohttp"
  } ],
  "database_specific" : {
    "cwe_ids" : [ "CWE-346" ],
    "severity" : "MODERATE",
    "github_reviewed" : true,
    "github_reviewed_at" : "2026-06-03T21:34:38Z",
    "nvd_published_at" : "2026-06-02T20:16:37Z"
  }
}