yhirose cpp-httplib up to 0.20.0 resource consumption

Summaryinfo

A vulnerability classified as problematic was found in yhirose cpp-httplib up to 0.20.0. This vulnerability affects unknown code. Executing a manipulation can lead to resource consumption. This vulnerability is tracked as CVE-2025-46728. The attack can be launched remotely. No exploit exists. Upgrading the affected component is advised.

Detailsinfo

A vulnerability has been found in yhirose cpp-httplib up to 0.20.0 and classified as problematic. This vulnerability affects an unknown function. The manipulation with an unknown input leads to a resource consumption vulnerability. The CWE definition for the vulnerability is CWE-400. The product does not properly control the allocation and maintenance of a limited resource, thereby enabling an actor to influence the amount of resources consumed, eventually leading to the exhaustion of available resources. As an impact it is known to affect availability. CVE summarizes:

cpp-httplib is a C++ header-only HTTP/HTTPS server and client library. Prior to version 0.20.1, the library fails to enforce configured size limits on incoming request bodies when `Transfer-Encoding: chunked` is used or when no `Content-Length` header is provided. A remote attacker can send a chunked request without the terminating zero-length chunk, causing uncontrolled memory allocation on the server. This leads to potential exhaustion of system memory and results in a server crash or unresponsiveness. Version 0.20.1 fixes the issue by enforcing limits during parsing. If the limit is exceeded at any point during reading, the connection is terminated immediately. A short-term workaround through a Reverse Proxy is available. If updating the library immediately is not feasible, deploy a reverse proxy (e.g., Nginx, HAProxy) in front of the `cpp-httplib` application. Configure the proxy to enforce maximum request body size limits, thereby stopping excessively large requests before they reach the vulnerable library code.

The advisory is shared for download at github.com. This vulnerability was named CVE-2025-46728 since 04/28/2025. 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 MITRE ATT&CK project declares the attack technique as T1499.

The vulnerability scanner Nessus provides a plugin with the ID 276114 (TencentOS Server 4: cpp-httplib (TSSA-2025:0374)), which helps to determine the existence of the flaw in a target environment.

Upgrading to version 0.20.1 eliminates this vulnerability. Applying the patch 7b752106ac42bd5b907793950d9125a0972c8e8e 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 vulnerability database at Tenable (276114). VulDB is the best source for vulnerability data and more expert information about this specific topic.

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

License

• open-source

Website

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

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VulDB is the best source for vulnerability data and more expert information about this specific topic.

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