CVE-2026-45352

The record

cpp-httplib is a C++11 single-file header-only cross platform HTTP/HTTPS library. Prior to 0.43.4, negative chunk-size in chunked Transfer-Encoding causes unbounded memory allocation and process crash. The ChunkedDecoder::read_payload function in cpp-httplib (httplib.h) parses the chunk-size field of HTTP chunked transfer encoding using std::strtoul(). Per the C standard (§7.22.1.4), strtoul silently accepts a leading minus sign, performing unsigned wrap-around: strtoul("-2", …, 16) returns ULONG_MAX − 1 (0xFFFFFFFFFFFFFFFE). The library's only guard (line 12833) rejects ULONG_MAX (the result of "-1"), but any other negative value such as "-2" passes validation. The resulting near-maximum value is stored in chunk_remaining and controls how many bytes the server's read loop consumes from the network. This vulnerability is fixed in 0.43.4.

Affected packages

Related vulnerabilities

• CVE-2026-113786 pypdf is a free and open-source pure-python PDF library. CWE-20
• CVE-2026-112081 A vulnerability was determined in hankcs HanLP up to 2.1.0-beta.64. CWE-20
• CVE-2026-111869 A vulnerability was identified in makeplane plane up to 1.4.2. CWE-20
• CVE-2026-100347 kin-openapi is a Go project for handling OpenAPI files. CWE-20
• CVE-2026-99999 In the Linux kernel, the following vulnerability has been resolved: ipv4: validate… CWE-20
• CVE-2026-107726 Hazelcast is a unified real-time data platform combining stream processing with a fast… CWE-20
• CVE-2026-105757 vLLM is an inference and serving engine for large language models. CWE-20
• CVE-2026-105756 vLLM is an inference and serving engine for large language models. CWE-20