HTTP Header Smuggling via Trailer Merge

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

Multiple directory traversal vulnerabilities in (1) mod_evhost and (2) mod_simple_vhost in lighttpd before 1.4.35 allow remote attackers to read arbitrary files via a .. (dot dot) in the host name, related to request_check_hostname.

mod_auth in lighttpd before 1.4.36 allows remote attackers to inject arbitrary log entries via a basic HTTP authentication string without a colon character, as demonstrated by a string containing a NULL and new line character.

SQL injection vulnerability in mod_mysql_vhost.c in lighttpd before 1.4.35 allows remote attackers to execute arbitrary SQL commands via the host name, related to request_check_hostname.

Use-after-free vulnerability in lighttpd before 1.4.33 allows remote attackers to cause a denial of service (segmentation fault and crash) via unspecified vectors that trigger FAMMonitorDirectory failures.

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.

The http_request_split_value function in request.c in lighttpd before 1.4.32 allows remote attackers to cause a denial of service (infinite loop) via a request with a header containing an empty token, as demonstrated using the "Connection: TE,,Keep-Alive" header.

The configuration file for the FastCGI PHP support for lighttpd before 1.4.28 on Debian GNU/Linux creates a socket file with a predictable name in /tmp, which allows local users to hijack the PHP control socket and perform unauthorized actions such as forcing the use of a different version of PHP via a symlink attack or a race condition.

lighttpd before 1.4.34, when SNI is enabled, configures weak SSL ciphers, which makes it easier for remote attackers to hijack sessions by inserting packets into the client-server data stream or obtain sensitive information by sniffing the network.

lighttpd before 1.4.33 does not check the return value of the (1) setuid, (2) setgid, or (3) setgroups functions, which might cause lighttpd to run as root if it is restarted and allows remote attackers to gain privileges, as demonstrated by multiple calls to the clone function that cause setuid to fail when the user process limit is reached.

lighttpd before 1.4.26, and 1.5.x, allocates a buffer for each read operation that occurs for a request, which allows remote attackers to cause a denial of service (memory consumption) by breaking a request into small pieces that are sent at a slow rate.

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.

In lighttpd 1.4.65, mod_wstunnel does not initialize a handler function pointer if an invalid HTTP request (websocket handshake) is received. It leads to null pointer dereference which crashes the server. It could be used by an external attacker to cause denial of service condition.

Lighttpd 1.4.56 through 1.4.58 allows a remote attacker to cause a denial of service (CPU consumption from stuck connections) because connection_read_header_more in connections.c has a typo that disrupts use of multiple read operations on large headers.

In lighttpd 1.4.46 through 1.4.63, the mod_extforward_Forwarded function of the mod_extforward plugin has a stack-based buffer overflow (4 bytes representing -1), as demonstrated by remote denial of service (daemon crash) in a non-default configuration. The non-default configuration requires handling of the Forwarded header in a somewhat unusual manner. Also, a 32-bit system is much more likely to be affected than a 64-bit system.

lighttpd before 1.4.54 has a signed integer overflow, which might allow remote attackers to cause a denial of service (application crash) or possibly have unspecified other impact via a malicious HTTP GET request, as demonstrated by mishandling of /%2F? in burl_normalize_2F_to_slash_fix in burl.c. NOTE: The developer states "The feature which can be abused to cause the crash is a new feature in lighttpd 1.4.50, and is not enabled by default. It must be explicitly configured in the config file (e.g. lighttpd.conf). Certain input will trigger an abort() in lighttpd when that feature is enabled. lighttpd detects the underflow or realloc() will fail (in both 32-bit and 64-bit executables), also detected in lighttpd. Either triggers an explicit abort() by lighttpd. This is not exploitable beyond triggering the explicit abort() with subsequent application exit.

An issue was discovered in mod_alias_physical_handler in mod_alias.c in lighttpd before 1.4.50. There is potential ../ path traversal of a single directory above an alias target, with a specific mod_alias configuration where the matched alias lacks a trailing '/' character, but the alias target filesystem path does have a trailing '/' character.