Description
Integer signedness error in the base64_decode function in the HTTP authentication functionality (http_auth.c) in lighttpd 1.4 before 1.4.30 and 1.5 before SVN revision 2806 allows remote attackers to cause a denial of service (segmentation fault) via crafted base64 input that triggers an out-of-bounds read with a negative index.
Fixed in Linux distributions
Distributions backport fixes, so the version that fixes this vulnerability differs per release — upgrade to at least the version shown. From the distributions' security trackers and advisories.
Debian
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Debian 14 | lighttpd | 1.4.30-1 | — |
| Debian 13 | lighttpd | 1.4.30-1 | — |
| Debian 12 | lighttpd | 1.4.30-1 | — |
| Debian 6.0 | lighttpd | 1.4.28-2+squeeze1 | DSA-2368-1 |
| Debian 5.0 | lighttpd | 1.4.19-5+lenny3 | DSA-2368-1 |
openSUSE
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| openSUSE Tumbleweed | lighttpd | 1.4.37-1.6 | openSUSE-SU-2024:10402-1 |
Public exploits
Exploit or proof-of-concept code for this vulnerability is publicly available, which lowers the bar for attackers. Treat it as a reason to patch sooner.
Exploit-DB 1
- lighttpd - Denial of Service (PoC) EDB-18295 · dos · Dec 31, 2011 · verified
Sources: PoC-in-GitHub, Metasploit Framework, Exploit-DB — updated daily. Only links are listed; no exploit code is hosted here.
Advisories 2
- DSA-2368-1 lighttpd - several Debian Security (DSA / DLA) · Mar 9, 2026
- openSUSE-SU-2024:10402-1 lighttpd-1.4.37-1.6 on GA media SUSE / openSUSE Security Updates · Feb 4, 2026
References
- 47260 third-party-advisory
- 20111224 Lighttpd Proof of Concept code for CVE-2011-4362 mailing-list
- [oss-security] 20111129 CVE Request: lighttpd/mod_auth out-of-bounds read due to signedness error mailing-list
- https://bugzilla.redhat.com/show_bug.cgi?id=758624
- DSA-2368 vendor-advisory
- 18295 exploit
- http://blog.pi3.com.pl/?p=277
- http://download.lighttpd.net/lighttpd/security/lighttpd_sa_2011_01.txt
- [oss-security] 20111129 Re: CVE Request: lighttpd/mod_auth out-of-bounds read due to signedness error mailing-list
- 1026359 vdb-entry
- lighttpd-base64-dos(71536) vdb-entry
- http://redmine.lighttpd.net/issues/2370
- JVN#37417423 third-party-advisory