Is aiohttp affected by CVE-2026-34517?

PyPI aiohttp is affected in <3.13.4.

Is CVE-2026-34517 being exploited?

Not on the CISA KEV list. EPSS exploit probability is 0.4%.

low

CVE-2026-34517

Q: Is CVE-2026-34517 being exploited?

Not on the CISA KEV list. EPSS exploit probability is 0.4%.

PyPI · aiohttp

Summary

AIOHTTP has late size enforcement for non-file multipart fields causes memory DoS

Severity: low
EPSS: 0.4% (p30)
Also known as: GHSA-3wq7-rqq7-wx6j
Published: 2026-04-01

References

https://github.com/aio-libs/aiohttp/security/advisories/GHSA-3wq7-rqq7-wx6j
https://nvd.nist.gov/vuln/detail/CVE-2026-34517
https://github.com/aio-libs/aiohttp/commit/cbb774f38330563422ca0c413a71021d7b944145

Related advisories

CVE-2025-69223 — high · PyPI/aiohttp
CVE-2026-54274 — medium · PyPI/aiohttp
CVE-2026-54273 — medium · PyPI/aiohttp
CVE-2026-54278 — medium · PyPI/aiohttp
CVE-2026-54277 — medium · PyPI/aiohttp
CVE-2026-54276 — medium · PyPI/aiohttp
CVE-2026-47265 — medium · PyPI/aiohttp
CVE-2026-34993 — medium · PyPI/aiohttp

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Sources: CISA KEV (public domain), OSV.dev & GitHub Advisory Database (CC-BY-4.0), FIRST EPSS, NVD/CWE (public domain). Served live from the Stateward advisory database.