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VulnerabilityPublished

CVE-2026-128128: aio-libs aiohttp · Unthrottled Resource Allocation

Affects aio-libs aiohttpSource CVE Database V5

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Not known to be exploited · CVSS 7.5 High : upgrade to 3.14.4 soon.

Data as of 13 Nov 2026, 20:48 UTC

CVSS 3.1 base score
7.5High
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 3.17.5
Patch
Available – fixed in 3.14.4
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

Exploitation evidence

  1. Disclosed: evidence found.

    CVE published 13 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 13 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 is required as the fix addresses the root cause.

Description

CVE-2026-128128 is a vulnerability in aiohttp versions prior to 3.14.4 where the C WebSocket reader uses signed 64-bit arithmetic to add a declared frame length to an already buffered partial message size. This can cause an integer overflow near 2^63, bypassing the max_msg_size check and allowing a remote attacker to cause unbounded memory consumption by sending a small non-final fragment followed by an oversized message. The Python WebSocket reader is not affected. The issue is fixed in version 3.14.4.

References

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