What is CVE-2025-53643?

CVE-2025-53643 is a high-severity vulnerability in Aiohttp, classified under Inconsistent Interpretation of HTTP Requests (HTTP Request/Response Smuggling). CVSS score: 7.5/10. Published 2025-07-14.

How severe is CVE-2025-53643?

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

Vulnerability in Aiohttp

CVE-2025-53643

AIOHTTP is an asynchronous HTTP client/server framework for asyncio and Python. Prior to version 3.12.14, the Python parser is vulnerable to a request smuggling vulnerability due to not parsing trailer sections of an HTTP request. If a pur…

Vulnerability class: HTTP Request Smuggling

EPSS: 0.003 (21.7th 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:H/A:N.

Affected products

Aiohttp
Aio-libs Aiohttp — versions < 3.12.14

Weakness classification (CWE)

CWE-444 — Inconsistent Interpretation of HTTP Requests (HTTP Request/Response Smuggling)

References

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

Frequently asked questions

What is CVE-2025-53643?: CVE-2025-53643 is a high-severity vulnerability in Aiohttp, classified under Inconsistent Interpretation of HTTP Requests (HTTP Request/Response Smuggling). CVSS score: 7.5/10. Published 2025-07-14.
How severe is CVE-2025-53643?: High severity. CVSS v3 base score is 7.5 out of 10.