CVE-2026-128131: aio-libs aiohttp · Uncontrolled Resource Consumption
Affects aio-libs aiohttpSource CVE Database V5
Not known to be exploited · CVSS 8.7 High : upgrade to 3.14.4 soon.
Data as of 13 Nov 2026, 21:02 UTC
Thin evidence
One scorer or none| CNA (GitHub_M) | CVSS 4.0 | 8.7 |
|---|
- Patch
- Available – fixed in 3.14.4
CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:NExploitation evidence
Disclosed: evidence found.
CVE published 13 Nov 2026
Detectable: no evidence on record.
No public nuclei template indexed
Weaponized: no evidence on record.
No public exploit code indexed in Metasploit or Exploit-DB
Exploited in the wildExploited: no evidence on record.
Not in CISA KEV and no source reports exploitation
Observed by OffSeq MirageSeen by Mirage: no evidence on record.
No attack traffic recorded by OffSeq Mirage sensors
A missing step is not evidence of safety. Sources: cve.org (opens in a new tab), the Metasploit, Exploit-DB and nuclei-templates index as of 13 Nov 2026.
What to do
Upgrade aio-libs aiohttp to 3.14.4.
Affected software
| Product | Affected | Fixed in |
|---|---|---|
| aio-libsaiohttp | Affected
| Fixed in
|
Description
AIOHTTP is an asynchronous HTTP client/server framework for asyncio and Python. Prior to 3.14.4, aiohttp decompresses each member of a payload containing many concatenated gzip, deflate, or zstd streams by passing the entire remaining input to a new decompressor, causing quadratic CPU use. Empty members produce no output, so client_max_size and output backpressure do not limit the work. A remote attacker can block a server event loop with a crafted compressed request body or WebSocket message, and a malicious server can similarly block a client. This issue is fixed in version 3.14.4.
References
- github.com/aio-libs/aiohttp/security/advisories/GHSA-h4cc-hm5h-fmm9 (opens in a new tab)
- github.com/aio-libs/aiohttp/pull/13362 (opens in a new tab)
- github.com/aio-libs/aiohttp/pull/13391 (opens in a new tab)
- github.com/aio-libs/aiohttp/commit/d041d4d0fd48c3f0832084d33be16cf1c4835f85 (opens in a new tab)
- github.com/aio-libs/aiohttp/commit/d925a80539ffd227da1d93ab4a5bff123cc777db (opens in a new tab)
- github.com/aio-libs/aiohttp/releases/tag/v3.14.4 (opens in a new tab)