CVE-2025-46728: high-severity vulnerability in yhirose cpp-httplib
cpp-httplib has Unbounded Memory Allocation in Chunked/No-Length Requests
Published
E-mail alert when it lands in KEV, gets a public PoC or its score goes up.
21Vexday Risk Score
No sign of exploitation. No public exploitation artifact known so far.
ssvc Trackcvss 7.5epss 0.7%
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.
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
Affected products
yhirose · cpp-httplibRelated CVEs — yhirose cpp-httplib
In the same product, most dangerous first.
CVE-2026-29076MEDIUMcpp-httplib: Stack Overflow Denial of Service (DoS) via std::regex in multipart filename parsingEPSS 0.7%CVE-2025-53629HIGHcpp-httplib Unbounded Memory Allocation in Chunked/No-Length Requests VulnerabilityEPSS 0.6%CVE-2025-53628MEDIUMcpp-httplib does not limit the length of a lineEPSS 0.5%CVE-2026-31870HIGHcpp-httplib Affected by Remote Process Crash via Malformed Content-Length Response HeaderEPSS 0.5%CVE-2025-52887HIGHcpp-httplib has unlimited number of http header fields, which causes memory leakEPSS 0.5%CVE-2026-28435HIGHPayload size limit bypass via gzip decompression in ContentReader (streaming) allows oversized request bodies in cpp-httplibEPSS 0.5%