Bug 2364271 (CVE-2025-46728)

Summary: CVE-2025-46728 cpp-httplib: cpp-httplib Chunked Request Memory Exhaustion
Product: [Other] Security Response Reporter: OSIDB Bzimport <bzimport>
Component: vulnerabilityAssignee: Product Security DevOps Team <prodsec-dev>
Status: NEW --- QA Contact:
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Priority: high    
Version: unspecifiedKeywords: Security
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Hardware: All   
OS: Linux   
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A flaw was found in cpp-httplib. This vulnerability allows for denial of service via oversized HTTP requests when using chunked transfer encoding or missing Content-Length headers, leading to uncontrolled memory allocation and potential server crash.
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Bug Depends On: 2364280, 2364281, 2364283, 2364284, 2364282    
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Description OSIDB Bzimport 2025-05-06 02:01:09 UTC 
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.