CVE-2026-34518
Authorization Header Disclosure in aiohttp Redirect Handling Prior to
Publication date: 2026-04-01
Last updated on: 2026-04-16
Assigner: GitHub, Inc.
Description
Description
CVSS Scores
EPSS Scores
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Meta Information
Affected Vendors & Products
| Vendor | Product | Version / Range |
|---|---|---|
| aiohttp | aiohttp | to 3.13.4 (exc) |
Helpful Resources
Exploitability
| CWE ID | Description |
|---|---|
| CWE-200 | The product exposes sensitive information to an actor that is not explicitly authorized to have access to that information. |
Attack-Flow Graph
AI Powered Q&A
Can you explain this vulnerability to me?
This vulnerability exists in the aiohttp framework prior to version 3.13.4. When aiohttp follows HTTP redirects to a different origin, it incorrectly drops the Authorization header while still retaining the Cookie and Proxy-Authorization headers.
This behavior can lead to unintended loss of authorization credentials during redirects, potentially affecting authentication flows.
The issue has been fixed in version 3.13.4 of aiohttp.
How can this vulnerability impact me? :
The impact of this vulnerability is that when an application using aiohttp follows redirects to a different origin, the Authorization header is dropped.
This could cause authentication failures or unexpected behavior in applications relying on the Authorization header for access control during redirects.
Since the Cookie and Proxy-Authorization headers are retained, some credentials may still be sent, but the loss of the Authorization header could lead to security or functionality issues depending on the application's design.
What immediate steps should I take to mitigate this vulnerability?
To mitigate this vulnerability, upgrade aiohttp to version 3.13.4 or later, where the issue has been patched.