CVE-2026-34518: CWE-200: Exposure of Sensitive Information to an Unauthorized Actor in aio-libs aiohttp
CVE-2026-34518 is a low-severity vulnerability in aiohttp versions prior to 3. 13. 4 where the Authorization header is improperly handled during redirects to a different origin. Specifically, while the Authorization header is dropped as intended, the Cookie and Proxy-Authorization headers are retained, potentially exposing sensitive information to unauthorized actors. This issue has been addressed in aiohttp version 3. 13. 4.
AI Analysis
Technical Summary
The vulnerability in aiohttp (an asynchronous HTTP client/server framework for Python) involves the handling of HTTP headers during redirects to a different origin. Before version 3.13.4, aiohttp drops the Authorization header on such redirects but incorrectly retains the Cookie and Proxy-Authorization headers. This behavior can lead to exposure of sensitive information (CWE-200) to unauthorized actors. The issue is fixed in version 3.13.4.
Potential Impact
The impact is limited to potential exposure of sensitive information contained in Cookie and Proxy-Authorization headers when aiohttp follows redirects to a different origin. The CVSS score of 2.7 (low severity) reflects that the vulnerability requires no privileges, no user interaction, and has low impact on confidentiality. There are no known exploits in the wild.
Mitigation Recommendations
Upgrade aiohttp to version 3.13.4 or later, where this issue has been patched. No other mitigation is indicated or necessary.
CVE-2026-34518: CWE-200: Exposure of Sensitive Information to an Unauthorized Actor in aio-libs aiohttp
Description
CVE-2026-34518 is a low-severity vulnerability in aiohttp versions prior to 3. 13. 4 where the Authorization header is improperly handled during redirects to a different origin. Specifically, while the Authorization header is dropped as intended, the Cookie and Proxy-Authorization headers are retained, potentially exposing sensitive information to unauthorized actors. This issue has been addressed in aiohttp version 3. 13. 4.
AI-Powered Analysis
Machine-generated threat intelligence
Technical Analysis
The vulnerability in aiohttp (an asynchronous HTTP client/server framework for Python) involves the handling of HTTP headers during redirects to a different origin. Before version 3.13.4, aiohttp drops the Authorization header on such redirects but incorrectly retains the Cookie and Proxy-Authorization headers. This behavior can lead to exposure of sensitive information (CWE-200) to unauthorized actors. The issue is fixed in version 3.13.4.
Potential Impact
The impact is limited to potential exposure of sensitive information contained in Cookie and Proxy-Authorization headers when aiohttp follows redirects to a different origin. The CVSS score of 2.7 (low severity) reflects that the vulnerability requires no privileges, no user interaction, and has low impact on confidentiality. There are no known exploits in the wild.
Mitigation Recommendations
Upgrade aiohttp to version 3.13.4 or later, where this issue has been patched. No other mitigation is indicated or necessary.
Technical Details
- Data Version
- 5.2
- Assigner Short Name
- GitHub_M
- Date Reserved
- 2026-03-30T16:03:31.047Z
- Cvss Version
- 4.0
- State
- PUBLISHED
Threat ID: 69ce7bdce6bfc5ba1ddfe7a7
Added to database: 4/2/2026, 2:23:24 PM
Last enriched: 4/10/2026, 12:10:38 AM
Last updated: 5/20/2026, 11:32:34 AM
Views: 81
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