What is CVE-2021-22960?

CVE-2021-22960 is a medium-severity vulnerability in Llhttp, classified under Inconsistent Interpretation of HTTP Requests (HTTP Request/Response Smuggling). CVSS score: 6.5/10. Published 2021-11-03.

How severe is CVE-2021-22960?

Medium severity. CVSS v3 base score is 6.5 out of 10.

Vulnerability in Llhttp

CVE-2021-22960

The parse function in llhttp < 2.1.4 and < 6.0.6. ignores chunk extensions when parsing the body of chunked requests. This leads to HTTP Request Smuggling (HRS) under certain conditions.

Vulnerability class: HTTP Request Smuggling

Published 2021-11-03 · last modified 2026-06-17.

CVSS v3 metric

CVSS v3 base score 6.5 (Medium). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:N.

EPSS exploit prediction

EPSS: 0.025 (83.9th percentile), scored 2026-09-28.

Low probability of exploitation in the next 30 days, but still tracked. 84th percentile — 83.9% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.

EPSS over last 30 days · oldest: 0.025 · newest: 0.025 · change: 0.000

Affected products

Llhttp
Node.js Node — versions 4.0, 5.0, 6.0
Oracle Graalvm — versions 20.3.4, 21.3.0
Debian Linux — versions 11.0

Weakness classification (CWE)

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

References

hackerone.com/reports/1238099 (Exploit, Third Party Advisory, Issue Tracking)
www.oracle.com/security-alerts/cpujan2022.html (Patch, Third Party Advisory)
www.debian.org/security/2022/dsa-5170 (vendor-advisory, Third Party Advisory)

Frequently asked questions

What is CVE-2021-22960?: CVE-2021-22960 is a medium-severity vulnerability in Llhttp, classified under Inconsistent Interpretation of HTTP Requests (HTTP Request/Response Smuggling). CVSS score: 6.5/10. Published 2021-11-03.
How severe is CVE-2021-22960?: Medium severity. CVSS v3 base score is 6.5 out of 10.