Is there a public exploit for CVE-2026-123817?

No public exploit for CVE-2026-123817 was found in Exploit-DB, Metasploit, Nuclei templates or public proof-of-concept repositories. That is an absence of evidence rather than proof that none exists.

How severe is CVE-2026-123817?

CVE-2026-123817 scores CVSS 8.7 (v4.0), rated high.

What does CVE-2026-123817 affect?

CVE-2026-123817 affects aio-libs aiohttp.

8.7 High

AIOHTTP is an asynchronous HTTP client/server framework for asyncio and Python.

CVE-2026-123817

AIOHTTP is an asynchronous HTTP client/server framework for asyncio and Python. Prior to 3.14.4, the WebSocket reader retains one bytes object for each transport read while reassembling an incomplete frame. A malicious peer can split a frame into many tiny reads so per-object overhead substantially exceeds the payload bytes allowed by maxmsgsize. The condition affects a server receiving frames from a malicious client and a client receiving frames from a malicious server, and can cause excessive memory consumption or denial of service. This issue is fixed in version 3.14.4.

Assessment

CVSS: 8.7 (v4.0)
Severity: High
Known exploited: Not listed in CISA KEV
Exploit availability: Nothing found in Exploit-DB, Metasploit, Nuclei or public PoC repositories
Published: 9 November 2026
Last updated: 9 November 2026
Affected: aio-libs · aiohttp
Assigner: GitHub_M

CVSS vectorCVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N

At the source

EUVD (ENISA)

References

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