CVE-2022-41556

Name: CVE-2022-41556
Creator: NVD / NIST
Published: 2022-10-06T18:17:03.62+00:00
License: https://creativecommons.org/publicdomain/zero/1.0/

HIGHCVSS 7.5/10EPSS 2.71%

Last modified Jun 17, 2026

CVE-2022-41556 is a high-severity vulnerability rated 7.5/10 on the CVSS scale. A resource leak in gw_backend.c in lighttpd 1.4.56 through 1.4.66 could lead to a denial of service (connection-slot exhaustion) after a large amount of anomalous TCP behavior by clients. It is related to RDHUP mishandling in certain HTTP/1.1 chunked situations. EPSS estimates a 2.71% chance of exploitation in the next 30 days.

Description

A resource leak in gw_backend.c in lighttpd 1.4.56 through 1.4.66 could lead to a denial of service (connection-slot exhaustion) after a large amount of anomalous TCP behavior by clients. It is related to RDHUP mishandling in certain HTTP/1.1 chunked situations. Use of mod_fastcgi is, for example, affected. This is fixed in 1.4.67.

Metrics

CVSS 3.1

7.5/10

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

EPSS Probability

2.71%

84.1th percentile

Probability of exploitation in the next 30 days. Learn more

Weakness Enumeration

CWE-401

Affected Software

Vendor	Product	Versions
Lighttpd	Lighttpd	>= 1.4.56, < 1.4.67
Fedoraproject	Fedora	35

References

https://git.lighttpd.net/lighttpd/lighttpd1.4/commit/b18de6f9264f914f7bf493abd3b6059343548e50Patch, Third Party Advisory
https://github.com/lighttpd/lighttpd1.4/compare/lighttpd-1.4.66...lighttpd-1.4.67Third Party Advisory
https://github.com/lighttpd/lighttpd1.4/pull/115Exploit, Issue Tracking, Third Party Advisory
https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/OVOSBSCMLGCHH2Z74H64ZWVDFJFQTBC2/
https://security.gentoo.org/glsa/202210-12Third Party Advisory
https://git.lighttpd.net/lighttpd/lighttpd1.4/commit/b18de6f9264f914f7bf493abd3b6059343548e50Patch, Third Party Advisory
https://github.com/lighttpd/lighttpd1.4/compare/lighttpd-1.4.66...lighttpd-1.4.67Third Party Advisory
https://github.com/lighttpd/lighttpd1.4/pull/115Exploit, Issue Tracking, Third Party Advisory
https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/OVOSBSCMLGCHH2Z74H64ZWVDFJFQTBC2/
https://security.gentoo.org/glsa/202210-12Third Party Advisory

Timeline

Published: Oct 6, 2022
Last Modified: Jun 17, 2026
Status: Modified

Frequently Asked Questions

What is CVE-2022-41556?

How severe is CVE-2022-41556?

CVE-2022-41556 has a CVSS score of 7.5/10 (HIGH severity). The EPSS model estimates a 2.71% probability of exploitation in the next 30 days.

How do I fix CVE-2022-41556?

Check the vendor references and advisories linked above for patched versions and mitigation guidance. You can also run a Strix scan to test if your systems are affected.

Are you affected by CVE-2022-41556?

Run a free Strix scan to check your systems for this vulnerability.

Scan your code now

Source: NVD / NIST