Description
lighttpd1.4.80 incorrectly merged trailer fields into headers after http request parsing. This behavior can be exploited to conduct HTTP Header Smuggling attacks.
Successful exploitation may allow an attacker to:
* Bypass access control rules
* Inject unsafe input into backend logic that trusts request headers
* Execute HTTP Request Smuggling attacks under some conditions
This issue affects lighttpd1.4.80
Affected products
| Vendor | Product | Affected | Fixed |
|---|---|---|---|
| lighttpd | lighttpd | 1.4.80 – < 1.4.81 | 1.4.81 |
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.
Ubuntu
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Ubuntu 26.10 | lighttpd | No fix yet | — |
| Ubuntu 26.04 LTS | lighttpd | No fix yet | — |
| Ubuntu 25.10 | lighttpd | No fix yet | — |
| Ubuntu 24.04 LTS | lighttpd | No fix yet | — |
| Ubuntu 22.04 LTS | lighttpd | No fix yet | — |
Show 4 more (older releases, extended support, other products)Fewer releases
| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Ubuntu 20.04 LTS | lighttpd | No fix yet | — |
| Ubuntu Pro 18.04 LTS | lighttpd | No fix yet | — |
| Ubuntu Pro 16.04 LTS | lighttpd | No fix yet | — |
| Ubuntu Pro 14.04 LTS | lighttpd | No fix yet | — |
Advisories 2
- WID-SEC-2026-1730 Xerox FreeFlow Print Server: Mehrere Schwachstellen ermöglichen nicht spezifizierten Angriff BSI CERT-Bund (WID) · Jul 16, 2026
- WID-SEC-2025-2477 lighttpd: Schwachstelle ermöglicht Umgehen von Sicherheitsvorkehrungen BSI CERT-Bund (WID) · Nov 3, 2025