CVE-2026-123817: aio-libs aiohttp · Unthrottled Resource Allocation
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 9 Nov 2026, 21:34 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 9 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 9 Nov 2026.
What to do
Upgrade aio-libs aiohttp to 3.14.4.
Affected software
| Product | Affected | Fixed in |
|---|---|---|
| aio-libsaiohttp | Affected
| Fixed in
|
AI-suggested
Upgrade aiohttp to version 3.14.4 or later, where this vulnerability is fixed. No other mitigation or workaround is indicated by the vendor advisory.
Description
CVE-2026-123817 is a high-severity vulnerability in aiohttp prior to version 3.14.4. It involves the WebSocket reader retaining one bytes object per transport read while reassembling incomplete frames, allowing a malicious peer to cause excessive memory consumption or denial of service by splitting a frame into many tiny reads. This affects both servers receiving frames from malicious clients and clients receiving frames from malicious servers. The issue is fixed in version 3.14.4.
References
- github.com/aio-libs/aiohttp/security/advisories/GHSA-2g87-pp6c-29x5 (opens in a new tab)
- github.com/aio-libs/aiohttp/pull/13352 (opens in a new tab)
- github.com/aio-libs/aiohttp/pull/13612 (opens in a new tab)
- github.com/aio-libs/aiohttp/commit/09bcaa73ff084a0c539bbf16a0a78743acb7141f (opens in a new tab)
- github.com/aio-libs/aiohttp/commit/6a4f6682817839313b04b8e5cea2b39c1a88ab4f (opens in a new tab)
- github.com/aio-libs/aiohttp/releases/tag/v3.14.4 (opens in a new tab)