What is CVE-2026-54278?

CVE-2026-54278 is a high-severity vulnerability in Aiohttp, classified under Improper Handling of Highly Compressed Data (Data Amplification). CVSS score: 7.5/10. Published 2026-06-22.

How severe is CVE-2026-54278?

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

Vulnerability in Aiohttp

CVE-2026-54278

AIOHTTP is an asynchronous HTTP client/server framework for asyncio and Python. Prior to 3.14.1, during cleanup it is possible for a compressed request body to be decompressed into memory in one chunk. An attacker may be able to send a com…

EPSS: 0.004 (32.4th 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 < 3.14.1

Weakness classification (CWE)

CWE-409 — Improper Handling of Highly Compressed Data (Data Amplification)

References

security-advisories@github.com (x_refsource_CONFIRM, Third Party Advisory)
security-advisories@github.com (Patch, x_refsource_MISC)

Frequently asked questions

What is CVE-2026-54278?: CVE-2026-54278 is a high-severity vulnerability in Aiohttp, classified under Improper Handling of Highly Compressed Data (Data Amplification). CVSS score: 7.5/10. Published 2026-06-22.
How severe is CVE-2026-54278?: High severity. CVSS v3 base score is 7.5 out of 10.