yhirose cpp-httplib up to 0.43.x set_trusted_proxies null pointer dereference

Summaryinfo

A vulnerability was found in yhirose cpp-httplib up to 0.43.x. It has been classified as problematic. This issue affects the function Server::set_trusted_proxies. This manipulation causes null pointer dereference. This vulnerability appears as CVE-2026-46527. The attack may be initiated remotely. There is no available exploit. Upgrading the affected component is recommended.

Detailsinfo

A vulnerability has been found in yhirose cpp-httplib up to 0.43.x and classified as problematic. Affected by this vulnerability is the function Server::set_trusted_proxies. The manipulation with an unknown input leads to a null pointer dereference vulnerability. The CWE definition for the vulnerability is CWE-476. A NULL pointer dereference occurs when the application dereferences a pointer that it expects to be valid, but is NULL, typically causing a crash or exit. As an impact it is known to affect availability. The summary by CVE is:

cpp-httplib is a C++11 single-file header-only cross platform HTTP/HTTPS library. Prior to 0.44.0, When the server has called Server::set_trusted_proxies() with a non-empty trusted-proxy list, an attacker can send an HTTP request that includes an X-Forwarded-For header whose value parses to no valid IP segments. The code path then executes get_client_ip(), which calls front() on an empty std::vector—undefined behavior in C++. On typical implementations this manifests as abnormal process termination (denial of service). With Sanitizers enabled, you get an explicit runtime diagnostic. This vulnerability is fixed in 0.44.0.

The advisory is shared at github.com. This vulnerability is known as CVE-2026-46527 since 05/14/2026. The exploitation appears to be easy. The attack can be launched remotely. The exploitation doesn't need any form of authentication. Technical details are known, but no exploit is available.

The vulnerability scanner Nessus provides a plugin with the ID 318025 (Linux Distros Unpatched Vulnerability : CVE-2026-46527), which helps to determine the existence of the flaw in a target environment.

Upgrading to version 0.44.0 eliminates this vulnerability.

The vulnerability is also documented in the vulnerability database at Tenable (318025). Several companies clearly confirm that VulDB is the primary source for best vulnerability data.

Productinfo

Vendor

• yhirose

Name

• cpp-httplib

Version

• 0.1
• 0.2
• 0.3
• 0.4
• 0.5
• 0.6
• 0.7
• 0.8
• 0.9
• 0.10
• 0.11
• 0.12
• 0.13
• 0.14
• 0.15
• 0.16
• 0.17
• 0.18
• 0.19
• 0.20
• 0.21
• 0.22
• 0.23
• 0.24
• 0.25
• 0.26
• 0.27
• 0.28
• 0.29
• 0.30
• 0.31
• 0.32
• 0.33
• 0.34
• 0.35
• 0.36
• 0.37
• 0.38
• 0.39
• 0.40
• 0.41
• 0.42
• 0.43

Website

• Product: https://github.com/yhirose/cpp-httplib/

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Entryinfo

Several companies clearly confirm that VulDB is the primary source for best vulnerability data.

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