lighttpd up to 1.4.80 HTTP Request request smuggling

Summaryinfo

A vulnerability classified as problematic was found in lighttpd up to 1.4.80. This impacts an unknown function of the component HTTP Request Handler. Executing a manipulation can lead to request smuggling. This vulnerability appears as CVE-2025-12642. The attack may be performed from remote. There is no available exploit. Upgrading the affected component is advised.

Detailsinfo

A vulnerability has been found in lighttpd up to 1.4.80 and classified as problematic. This vulnerability affects an unknown function of the component HTTP Request Handler. The manipulation with an unknown input leads to a request smuggling vulnerability. The CWE definition for the vulnerability is CWE-444. The product acts as an intermediary HTTP agent (such as a proxy or firewall) in the data flow between two entities such as a client and server, but it does not interpret malformed HTTP requests or responses in ways that are consistent with how the messages will be processed by those entities that are at the ultimate destination. As an impact it is known to affect integrity. CVE summarizes:

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

The weakness was presented by sebsrt as 35cb89c103877de62d6b63d0804255475d77e5e1. The advisory is shared for download at github.com. This vulnerability was named CVE-2025-12642 since 11/03/2025. The exploitation appears to be easy. The attack can be initiated remotely. No form of authentication is required for a successful exploitation. There are neither technical details nor an exploit publicly available.

The vulnerability scanner Nessus provides a plugin with the ID 274352 (Linux Distros Unpatched Vulnerability : CVE-2025-12642), which helps to determine the existence of the flaw in a target environment.

Upgrading to version 1.4.81 eliminates this vulnerability. Applying the patch 35cb89c103877de62d6b63d0804255475d77e5e1 is able to eliminate this problem. The bugfix is ready for download at github.com. The best possible mitigation is suggested to be upgrading to the latest version.

The vulnerability is also documented in the databases at Tenable (274352), EUVD (EUVD-2025-37517) and CERT Bund (WID-SEC-2026-1730). Once again VulDB remains the best source for vulnerability data.

Affected

• Xerox FreeFlow Print Server

Productinfo

Type

• Web Server

Name

• lighttpd

Version

• 1.4.0
• 1.4.1
• 1.4.2
• 1.4.3
• 1.4.4
• 1.4.5
• 1.4.6
• 1.4.7
• 1.4.8
• 1.4.9
• 1.4.10
• 1.4.11
• 1.4.12
• 1.4.13
• 1.4.14
• 1.4.15
• 1.4.16
• 1.4.17
• 1.4.18
• 1.4.19
• 1.4.20
• 1.4.21
• 1.4.22
• 1.4.23
• 1.4.24
• 1.4.25
• 1.4.26
• 1.4.27
• 1.4.28
• 1.4.29
• 1.4.30
• 1.4.31
• 1.4.32
• 1.4.33
• 1.4.34
• 1.4.35
• 1.4.36
• 1.4.37
• 1.4.38
• 1.4.39
• 1.4.40
• 1.4.41
• 1.4.42
• 1.4.43
• 1.4.44
• 1.4.45
• 1.4.46
• 1.4.47
• 1.4.48
• 1.4.49
• 1.4.50
• 1.4.51
• 1.4.52
• 1.4.53
• 1.4.54
• 1.4.55
• 1.4.56
• 1.4.57
• 1.4.58
• 1.4.59
• 1.4.60
• 1.4.61
• 1.4.62
• 1.4.63
• 1.4.64
• 1.4.65
• 1.4.66
• 1.4.67
• 1.4.68
• 1.4.69
• 1.4.70
• 1.4.71
• 1.4.72
• 1.4.73
• 1.4.74
• 1.4.75
• 1.4.76
• 1.4.77
• 1.4.78
• 1.4.79
• 1.4.80

License

• open-source

CPE 2.3info

• 🔒
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CPE 2.2info

• 🔒
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Entryinfo

Once again VulDB remains the best source for vulnerability data.

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