What is CVE-2026-34516?

CVE-2026-34516 is a high-severity vulnerability in Aiohttp, classified under Allocation of Resources Without Limits or Throttling. CVSS score: 7.5/10. Published 2026-04-01.

How severe is CVE-2026-34516?

High severity. CVSS v3 base score is 7.5 out of 10.

Resource exhaustion in Aiohttp

CVE-2026-34516

AIOHTTP is an asynchronous HTTP client/server framework for asyncio and Python. Prior to version 3.13.4, a response with an excessive number of multipart headers may be allowed to use more memory than intended, potentially allowing a DoS v…

EPSS: 0.004 (35.8th percentile) — read the EPSS interpretation.

CVSS v3 metric

CVSS v3 base score 7.5 (High). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H.

Affected products

Aiohttp
Aio-libs Aiohttp — versions < 3.13.4

Weakness classification (CWE)

CWE-770 — Allocation of Resources Without Limits or Throttling

References

security-advisories@github.com (x_refsource_CONFIRM, Patch, Vendor Advisory)
security-advisories@github.com (Patch, x_refsource_MISC)
security-advisories@github.com (x_refsource_MISC, Release Notes)

Frequently asked questions

What is CVE-2026-34516?: CVE-2026-34516 is a high-severity vulnerability in Aiohttp, classified under Allocation of Resources Without Limits or Throttling. CVSS score: 7.5/10. Published 2026-04-01.
How severe is CVE-2026-34516?: High severity. CVSS v3 base score is 7.5 out of 10.