CVE-2022-41556 — A resource leak in gw_backend
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_fastcg
Published
2022-10-06T00:00:00.000Z
Last modified
2024-08-03T12:42:46.654Z
01What is this vulnerability?
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.
02Affected products
| Vendor | Product | Versions |
|---|
| n | a / n/a | n/a |
03Active exploitation status
Not currently listed on the CISA Known Exploited Vulnerabilities (KEV) catalog. EPSS is the best forward-looking signal — see the EPSS row above.
04Recommended remediation
- Patch to a fixed version listed in the vendor advisory (see references below).
- Mitigate with WAF rules, network egress filters, or feature flags where the patch is not yet available.
- Hunt historical logs for exploitation indicators — see Detection signatures below.
05Technical details
For the full vendor write-up, exploit chains, and reference implementations, see the references list in section 09.
06Detection signatures
Ask SARA in chat to draft a starting detection for this CVE in your stack of choice.
07Related CVEs
No directly-cited follow-up CVEs in the KB record for this advisory. The references list in section 09 carries the vendor cross-references.
08Timeline
- Published: 2022-10-06T00:00:00.000Z
- Last modified: 2024-08-03T12:42:46.654Z
09References
- git.lighttpd.net — https://git.lighttpd.net/lighttpd/lighttpd1.4/commit/b18de6f9264f914f7bf493abd3b…
- github.com — https://github.com/lighttpd/lighttpd1.4/pull/115
- github.com — https://github.com/lighttpd/lighttpd1.4/compare/lighttpd-1.4.66...lighttpd-1.4.6…
- lists.fedoraproject.org — https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedorapro…
- security.gentoo.org — https://security.gentoo.org/glsa/202210-12
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