Skip to main content
VulnerabilityPublished

CVE-2026-123817: aio-libs aiohttp · Unthrottled Resource Allocation

Affects aio-libs aiohttpSource CVE Database V5

0
Compare

Not known to be exploited · CVSS 8.7 High : upgrade to 3.14.4 soon.

Data as of 9 Nov 2026, 21:34 UTC

CVSS 4.0 base score
8.7High
How severe the flaw is on the 0–10 CVSS scale.

Thin evidence

One scorer or none
CVSS scores by source
CNA (GitHub_M)CVSS 4.08.7
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:N

Exploitation evidence

  1. Disclosed: evidence found.

    CVE published 9 Nov 2026

  2. Detectable: no evidence on record.

    No public nuclei template indexed

  3. Weaponized: no evidence on record.

    No public exploit code indexed in Metasploit or Exploit-DB

  4. Exploited in the wild: no evidence on record.

    Not in CISA KEV and no source reports exploitation

  5. Observed by OffSeq 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

ProductAffectedFixed in
aio-libsaiohttpAffected
  • <3.14.4
Fixed in
  • 3.14.4

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

Community reviews

Loading reviews…