CVE-2026-47265 AIOHTTP vulnerable to cross-origin redirect with per-request cookies
Attackers can steal sensitive cookies from per-request HTTP calls if they control a cross-origin redirect, affecting developers using the aiohttp library.
- Exploited in the wild
- Not known
- Login needed
- Not needed
- Attackable
- Over the internet
- Victim action needed
- Not needed
- Fix
- Available
What is CVE-2026-47265?
CVE-2026-47265 is a medium-severity vulnerability in aio-libs aiohttp, published on 2 Jun 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.
Official description
AIOHTTP is an asynchronous HTTP client/server framework for asyncio and Python. Prior to version 3.14.0, cookies set with the `cookies` parameter on requests are sent after following a cross-origin redirect. 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. Version 3.14.0 patches the issue. If unable to upgrade, using a `Cookie` header in the `headers` parameter is not vulnerable.
Weakness: CWE-346
Which versions are affected by CVE-2026-47265?
3 open source packages ship an affected version, including aiohttp. It affects 1 product.
| Package | Affected | Fixed in |
|---|---|---|
aiohttp PyPI | All versions | 3.14.0 |
aiohttp PyPI | All versions | 3.14.0 |
aiohttp PyPI | All versions | 3.14.0 |
Products include Aiohttp Aiohttp.
How do I fix CVE-2026-47265?
Upgrade aiohttp to 3.14.0 or later.
Is CVE-2026-47265 being exploited?
There is no known exploitation of CVE-2026-47265 in the wild and no public exploit code.
Other vulnerabilities in aio-libs aiohttp
- CVE-2024-52303 aiohttp memory leak when middleware is enabled when requesting a resource with a non-allowed method
- CVE-2025-69223 AIOHTTP's HTTP Parser auto_decompress feature is vulnerable to zip bomb
- CVE-2024-30251 Denial of service when trying to parse malformed POST requests in aiohttp
- CVE-2023-49081 aiohttp's ClientSession is vulnerable to CRLF injection via version
- CVE-2026-22815 AIOHTTP: Uncapped memory usage possible through aiohttp allowing unlimited trailer headers
Sources
Also known as AZL-89333, CLEANSTART-2026-IS85221, CLEANSTART-2026-MJ80904, CLSA-2026-1781830554, DEBIAN-CVE-2026-47265, ECHO-9113-79e2-ca65 and 20 more.