# CVE-2026-123817: AIOHTTP WebSocket frame reassembly permits excessive memory consumption from tiny reads

Status: published. Published: 2026-11-09. Updated: 2026-11-09.

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 max_msg_size. 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.

## Remediation

- fix: aiohttp (PyPI): OSV reports a fixed version 3.14.4. Check the advisory for supported release branches. (source: OSV GHSA-2g87-pp6c-29x5) — https://github.com/advisories/GHSA-2g87-pp6c-29x5

## Affected products and versions

- aio-libs / aiohttp: < 3.14.4 (affected). Source: CNA: GitHub_M
-  / aiohttp (aiohttp): 0.1 (affected, PyPI); 0.10.0 (affected, PyPI); 0.10.1 (affected, PyPI); 0.10.2 (affected, PyPI); 0.11.0 (affected, PyPI); 0.12.0 (affected, PyPI); 0.13.0 (affected, PyPI); 0.13.1 (affected, PyPI); 0.14.0 (affected, PyPI); 0.14.1 (affected, PyPI); 0.14.2 (affected, PyPI); 0.14.3 (affected, PyPI); 0.14.4 (affected, PyPI); 0.15.0 (affected, PyPI); 0.15.1 (affected, PyPI); 0.15.2 (affected, PyPI); 0.15.3 (affected, PyPI); 0.16.0 (affected, PyPI); 0.16.1 (affected, PyPI); 0.16.2 (affected, PyPI); 0.16.3 (affected, PyPI); 0.16.4 (affected, PyPI); 0.16.5 (affected, PyPI); 0.16.6 (affected, PyPI); 0.17.0 (affected, PyPI); 0.17.1 (affected, PyPI); 0.17.2 (affected, PyPI); 0.17.3 (affected, PyPI); 0.17.4 (affected, PyPI); 0.18.0 (affected, PyPI); 0.18.1 (affected, PyPI); 0.18.2 (affected, PyPI); 0.18.3 (affected, PyPI); 0.18.4 (affected, PyPI); 0.19.0 (affected, PyPI); 0.2 (affected, PyPI); 0.20.0 (affected, PyPI); 0.20.1 (affected, PyPI); 0.20.2 (affected, PyPI); 0.21.0 (affected, PyPI); 0.21.1 (affected, PyPI); 0.21.2 (affected, PyPI); 0.21.4 (affected, PyPI); 0.21.5 (affected, PyPI); 0.21.6 (affected, PyPI); 0.22.0 (affected, PyPI); 0.22.0a0 (affected, PyPI); 0.22.0b0 (affected, PyPI); 0.22.0b1 (affected, PyPI); 0.22.0b2 (affected, PyPI); 0.22.0b3 (affected, PyPI); 0.22.0b4 (affected, PyPI); 0.22.0b5 (affected, PyPI); 0.22.0b6 (affected, PyPI); 0.22.1 (affected, PyPI); 0.22.2 (affected, PyPI); 0.22.3 (affected, PyPI); 0.22.4 (affected, PyPI); 0.22.5 (affected, PyPI); 0.3 (affected, PyPI); 0.4 (affected, PyPI); 0.4.1 (affected, PyPI); 0.4.2 (affected, PyPI); 0.4.3 (affected, PyPI); 0.4.4 (affected, PyPI); 0.5.0 (affected, PyPI); 0.6.0 (affected, PyPI); 0.6.1 (affected, PyPI); 0.6.2 (affected, PyPI); 0.6.3 (affected, PyPI); 0.6.4 (affected, PyPI); 0.6.5 (affected, PyPI); 0.7.0 (affected, PyPI); 0.7.1 (affected, PyPI); 0.7.2 (affected, PyPI); 0.7.3 (affected, PyPI); 0.8.0 (affected, PyPI); 0.8.1 (affected, PyPI); 0.8.2 (affected, PyPI); 0.8.3 (affected, PyPI); 0.8.4 (affected, PyPI); 0.9.0 (affected, PyPI); 0.9.1 (affected, PyPI); 0.9.2 (affected, PyPI); 0.9.3 (affected, PyPI); 1.0.0 (affected, PyPI); 1.0.1 (affected, PyPI); 1.0.2 (affected, PyPI); 1.0.3 (affected, PyPI); 1.0.5 (affected, PyPI); 1.1.0 (affected, PyPI); 1.1.1 (affected, PyPI); 1.1.2 (affected, PyPI); 1.1.3 (affected, PyPI); 1.1.4 (affected, PyPI); 1.1.5 (affected, PyPI); 1.1.6 (affected, PyPI); 1.2.0 (affected, PyPI); 1.3.0 (affected, PyPI); 1.3.1 (affected, PyPI); 1.3.2 (affected, PyPI); 1.3.3 (affected, PyPI); 1.3.4 (affected, PyPI); 1.3.5 (affected, PyPI); 2.0.0 (affected, PyPI); 2.0.0rc1 (affected, PyPI); 2.0.1 (affected, PyPI); 2.0.2 (affected, PyPI); 2.0.3 (affected, PyPI); 2.0.4 (affected, PyPI); 2.0.5 (affected, PyPI); 2.0.6 (affected, PyPI); 2.0.7 (affected, PyPI); 2.1.0 (affected, PyPI); 2.2.0 (affected, PyPI); 2.2.1 (affected, PyPI); 2.2.2 (affected, PyPI); 2.2.3 (affected, PyPI); 2.2.4 (affected, PyPI); 2.2.5 (affected, PyPI); 2.3.0 (affected, PyPI); 2.3.0a1 (affected, PyPI); 2.3.0a2 (affected, PyPI); 2.3.0a3 (affected, PyPI); 2.3.0a4 (affected, PyPI); 2.3.1 (affected, PyPI); 2.3.10 (affected, PyPI); 2.3.1a1 (affected, PyPI); 2.3.2 (affected, PyPI); 2.3.2b2 (affected, PyPI); 2.3.2b3 (affected, PyPI); 2.3.3 (affected, PyPI); 2.3.4 (affected, PyPI); 2.3.5 (affected, PyPI); 2.3.6 (affected, PyPI); 2.3.7 (affected, PyPI); 2.3.8 (affected, PyPI); 2.3.9 (affected, PyPI); 3.0.0 (affected, PyPI); 3.0.0b0 (affected, PyPI); 3.0.0b1 (affected, PyPI); 3.0.0b2 (affected, PyPI); 3.0.0b3 (affected, PyPI); 3.0.0b4 (affected, PyPI); 3.0.1 (affected, PyPI); 3.0.2 (affected, PyPI); 3.0.3 (affected, PyPI); 3.0.4 (affected, PyPI); 3.0.5 (affected, PyPI); 3.0.6 (affected, PyPI); 3.0.7 (affected, PyPI); 3.0.8 (affected, PyPI); 3.0.9 (affected, PyPI); 3.1.0 (affected, PyPI); 3.1.1 (affected, PyPI); 3.1.2 (affected, PyPI); 3.1.3 (affected, PyPI); 3.10.0 (affected, PyPI); 3.10.0b1 (affected, PyPI); 3.10.0rc0 (affected, PyPI); 3.10.1 (affected, PyPI); 3.10.10 (affected, PyPI); 3.10.11 (affected, PyPI); 3.10.11rc0 (affected, PyPI); 3.10.2 (affected, PyPI); 3.10.3 (affected, PyPI); 3.10.4 (affected, PyPI); 3.10.5 (affected, PyPI); 3.10.6 (affected, PyPI); 3.10.6rc0 (affected, PyPI); 3.10.6rc1 (affected, PyPI); 3.10.6rc2 (affected, PyPI); 3.10.7 (affected, PyPI); 3.10.8 (affected, PyPI); 3.10.9 (affected, PyPI); 3.11.0 (affected, PyPI); 3.11.0b0 (affected, PyPI); 3.11.0b1 (affected, PyPI); 3.11.0b2 (affected, PyPI); 3.11.0b3 (affected, PyPI); 3.11.0b4 (affected, PyPI); 3.11.0b5 (affected, PyPI); 3.11.0rc0 (affected, PyPI); 3.11.0rc1 (affected, PyPI); 3.11.0rc2 (affected, PyPI); 3.11.1 (affected, PyPI); 3.11.10 (affected, PyPI); 3.11.11 (affected, PyPI); 3.11.12 (affected, PyPI); 3.11.13 (affected, PyPI); 3.11.14 (affected, PyPI); 3.11.15 (affected, PyPI); 3.11.16 (affected, PyPI); 3.11.17 (affected, PyPI); 3.11.18 (affected, PyPI); 3.11.2 (affected, PyPI); 3.11.3 (affected, PyPI); 3.11.4 (affected, PyPI); 3.11.5 (affected, PyPI); 3.11.6 (affected, PyPI); 3.11.7 (affected, PyPI); 3.11.8 (affected, PyPI); 3.11.9 (affected, PyPI); 3.12.0 (affected, PyPI); 3.12.0b0 (affected, PyPI); 3.12.0b1 (affected, PyPI); 3.12.0b2 (affected, PyPI); 3.12.0b3 (affected, PyPI); 3.12.0rc0 (affected, PyPI); 3.12.0rc1 (affected, PyPI); 3.12.1 (affected, PyPI); 3.12.10 (affected, PyPI); 3.12.11 (affected, PyPI); 3.12.12 (affected, PyPI); 3.12.13 (affected, PyPI); 3.12.14 (affected, PyPI); 3.12.15 (affected, PyPI); 3.12.1rc0 (affected, PyPI); 3.12.2 (affected, PyPI); 3.12.3 (affected, PyPI); 3.12.4 (affected, PyPI); 3.12.6 (affected, PyPI); 3.12.7 (affected, PyPI); 3.12.7rc0 (affected, PyPI); 3.12.8 (affected, PyPI); 3.12.9 (affected, PyPI); 3.13.0 (affected, PyPI); 3.13.1 (affected, PyPI); 3.13.2 (affected, PyPI); 3.13.3 (affected, PyPI); 3.13.4 (affected, PyPI); 3.13.5 (affected, PyPI); 3.14.0 (affected, PyPI); 3.14.1 (affected, PyPI); 3.14.2 (affected, PyPI); 3.14.3 (affected, PyPI); 3.2.0 (affected, PyPI); 3.2.1 (affected, PyPI); 3.3.0 (affected, PyPI); 3.3.0a0 (affected, PyPI); 3.3.1 (affected, PyPI); 3.3.2 (affected, PyPI); 3.3.2a0 (affected, PyPI); 3.4.0 (affected, PyPI); 3.4.0a0 (affected, PyPI); 3.4.0a3 (affected, PyPI); 3.4.0b1 (affected, PyPI); 3.4.0b2 (affected, PyPI); 3.4.1 (affected, PyPI); 3.4.2 (affected, PyPI); 3.4.3 (affected, PyPI); 3.4.4 (affected, PyPI); 3.5.0 (affected, PyPI); 3.5.0a1 (affected, PyPI); 3.5.0b1 (affected, PyPI); 3.5.0b2 (affected, PyPI); 3.5.0b3 (affected, PyPI); 3.5.1 (affected, PyPI); 3.5.2 (affected, PyPI); 3.5.3 (affected, PyPI); 3.5.4 (affected, PyPI); 3.6.0 (affected, PyPI); 3.6.0a0 (affected, PyPI); 3.6.0a1 (affected, PyPI); 3.6.0a11 (affected, PyPI); 3.6.0a12 (affected, PyPI); 3.6.0a2 (affected, PyPI); 3.6.0a3 (affected, PyPI); 3.6.0a4 (affected, PyPI); 3.6.0a5 (affected, PyPI); 3.6.0a6 (affected, PyPI); 3.6.0a7 (affected, PyPI); 3.6.0a8 (affected, PyPI); 3.6.0a9 (affected, PyPI); 3.6.0b0 (affected, PyPI); 3.6.1 (affected, PyPI); 3.6.1b3 (affected, PyPI); 3.6.1b4 (affected, PyPI); 3.6.2 (affected, PyPI); 3.6.2a0 (affected, PyPI); 3.6.2a1 (affected, PyPI); 3.6.2a2 (affected, PyPI); 3.6.3 (affected, PyPI); 3.7.0 (affected, PyPI); 3.7.0b0 (affected, PyPI); 3.7.0b1 (affected, PyPI); 3.7.1 (affected, PyPI); 3.7.2 (affected, PyPI); 3.7.3 (affected, PyPI); 3.7.4 (affected, PyPI); 3.7.4.post0 (affected, PyPI); 3.8.0 (affected, PyPI); 3.8.0a7 (affected, PyPI); 3.8.0b0 (affected, PyPI); 3.8.1 (affected, PyPI); 3.8.2 (affected, PyPI); 3.8.3 (affected, PyPI); 3.8.4 (affected, PyPI); 3.8.5 (affected, PyPI); 3.8.6 (affected, PyPI); 3.9.0 (affected, PyPI); 3.9.0b0 (affected, PyPI); 3.9.0b1 (affected, PyPI); 3.9.0rc0 (affected, PyPI); 3.9.1 (affected, PyPI); 3.9.2 (affected, PyPI); 3.9.3 (affected, PyPI); 3.9.4 (affected, PyPI); 3.9.4rc0 (affected, PyPI); 3.9.5 (affected, PyPI); Ecosystem version events: introduced 0; fixed 3.14.4. Source: OSV GHSA-2g87-pp6c-29x5

## Severity and prioritization

- CVSS 4.0: 8.7 (high); 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; source: CNA: GitHub_M

- CISA KEV: No listing in collected sources

- EPSS: Not available

- SSVC: Not available

- Weaknesses: CWE-770

## Exploit evidence

No exploit evidence in collected sources. This is not proof of no exploitation.

## References

- https://github.com/aio-libs/aiohttp/security/advisories/GHSA-2g87-pp6c-29x5 (CNA: GitHub_M; x_refsource_CONFIRM)

- https://github.com/aio-libs/aiohttp/pull/13352 (CNA: GitHub_M; x_refsource_MISC)

- https://github.com/aio-libs/aiohttp/pull/13612 (CNA: GitHub_M; x_refsource_MISC)

- https://github.com/aio-libs/aiohttp/commit/09bcaa73ff084a0c539bbf16a0a78743acb7141f (CNA: GitHub_M; x_refsource_MISC)

- https://github.com/aio-libs/aiohttp/commit/6a4f6682817839313b04b8e5cea2b39c1a88ab4f (CNA: GitHub_M; x_refsource_MISC)

- https://github.com/aio-libs/aiohttp/releases/tag/v3.14.4 (CNA: GitHub_M; x_refsource_MISC)

- https://github.com/advisories/GHSA-2g87-pp6c-29x5 (OSV / GitHub Security Advisories; advisory)

- https://osv.dev/vulnerability/GHSA-2g87-pp6c-29x5 (OSV / GitHub Security Advisories; osv)

## Provenance

- CNA: GitHub_M: https://www.cve.org/CVERecord?id=CVE-2026-123817; retrieved 2026-11-09; source updated 2026-11-09

- OSV / GitHub Security Advisories: https://osv.dev/vulnerability/GHSA-2g87-pp6c-29x5; retrieved 2026-11-09; source updated 2026-11-09

Revision: 2a2a750df795909894244d5bf327b2551286b5e3449db1495052f039c77a4c62

Canonical: https://y2.dev/cve/CVE-2026-123817

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