CVE-2026-59881 Details
Description
AIOHTTP is an asynchronous HTTP client/server framework for asyncio and Python. Prior to 3.14.2, the WebSocket client accepts and decompresses frames with the RSV1 bit set even when the permessage-deflate extension was not negotiated, allowing a malicious server to cause unexpected CPU and memory consumption. This issue is fixed in version 3.14.2.
A vulnerability exists in the AIOHTTP WebSocket client, specifically in versions prior to 3.14.2. The issue arises because the client decompresses WebSocket frames with the RSV1 bit set, even when the permessage-deflate extension has not been negotiated. This behavior can be exploited by a malicious server to cause unexpected consumption of CPU and memory resources. The vulnerability is particularly concerning in the presence of a zip bomb or similar attack.
Users can upgrade to AIOHTTP version 3.14.2 or later, where this vulnerability has been fixed.
Metrics
CVSS 4.0 Severity and Vector Strings:
VolerionCVSS 3.x Severity and Vector Strings:
No data available for CVSS Version 2.0 on this CVE.
Volerion
Assessed Jul 30, 2026CISA-ADP
Assessed Jul 30, 2026References to Advisories, Solutions, and Tools
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| URL | Source(s) | Tag(s) |
|---|---|---|
| http://github.com/aio-libs/aiohttp/releases/tag/v3.14.2 | [email protected] | Release NotesVendor |
| https://github.com/aio-libs/aiohttp/commit/47fb6ae354d4fa22048f4dbe7dbf82b625f0a2f6 | [email protected] | Source CodeVendor |
| https://github.com/aio-libs/aiohttp/pull/12978 | [email protected] | Source CodeVendor |
| https://github.com/aio-libs/aiohttp/security/advisories/GHSA-mq44-7p77-q5h7 | [email protected] | AdvisoryRemedyVendor |
Weakness Enumeration
| CWE-ID | CWE Name | Source |
|---|---|---|
| CWE-20 | Improper Input Validation | [email protected] |
Affected Products
| Product | Versions |
|---|---|
| aiohttp | <= 3.14.1 (semver) |
CPE
Remediation
| |
Change History
2 change records found show changes
| Date | Action | Recorded By |
|---|---|---|
| Jul 30, 2026 | New CVE Received | [email protected] |
| Jul 30, 2026 | CVE Modified | CISA-ADP |