{"id":"CVE-2026-45352","summary":"cpp-httplib DoS: Negative chunk-size in chunked Transfer-Encoding","details":"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.","aliases":["GHSA-h6wq-j5mv-f3q8"],"modified":"2026-07-15T01:49:02.026433565Z","published":"2026-05-29T19:14:08.065Z","database_specific":{"osv_generated_from":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/45xxx/CVE-2026-45352.json","cna_assigner":"GitHub_M","cwe_ids":["CWE-1285","CWE-20","CWE-770"]},"references":[{"type":"ADVISORY","url":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/45xxx/CVE-2026-45352.json"},{"type":"ADVISORY","url":"https://github.com/yhirose/cpp-httplib/security/advisories/GHSA-h6wq-j5mv-f3q8"},{"type":"ADVISORY","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-45352"}],"affected":[{"ranges":[{"type":"GIT","repo":"https://github.com/yhirose/cpp-httplib","events":[{"introduced":"0"},{"fixed":"600d220c84853f52011ae4b95fc8518742bcdfac"}],"database_specific":{"extracted_events":[{"introduced":"0"},{"fixed":"0.43.4"}],"source":["AFFECTED_FIELD","CPE_RANGE"],"cpe":"cpe:2.3:a:yhirose:cpp-httplib:*:*:*:*:*:*:*:*"}}],"versions":["v0.43.3","v0.43.2","v0.43.1","v0.43.0","v0.42.0","v0.41.0","v0.40.0","v0.39.0","v0.38.0","v0.37.2","v0.37.1","v0.37.0","v0.35.0","v0.34.0","latest","v0.33.1","v0.33.0","v0.32.0","v0.31.0","v0.30.2","v0.30.1","v0.30.0","v0.29.0","v0.28.0","v0.27.0","v0.26.0","v0.25.0","v0.24.0","v0.23.1","v0.23.0","v0.22.0","v0.21.0","v0.20.1","v0.20.0","v0.19.0","v0.18.7","v0.18.6","v0.18.5","v0.18.4","v0.18.3","v0.18.2","v0.18.1","v0.18.0","v0.17.3","v0.17.2","v0.17.1","v0.17.0","v0.16.3","v0.16.2","v0.16.1","v0.16.0","v0.15.3","v0.15.2","v0.15.1","v0.15.0","v0.14.3","v0.14.2","v0.14.1","v0.14.0","v0.13.3","v0.13.2","v0.13.1","v0.13.0","v0.12.6","v0.12.5","v0.12.4","v0.12.3","v0.12.2","v0.12.1","v0.12.0","v0.11.4","v0.11.3","v0.11.2","v0.11.1","v0.11.0","v0.10.9","v0.10.8","v0.10.7","v0.10.6","v0.10.5","v0.10.4","v0.10.3","v0.10.2","v0.10.1","v0.10.0","v0.9.10","v0.9.9","v0.9.8","v0.9.7","v0.9.6","v0.9.5","v0.9.4","v0.9.3","v0.9.2","v0.9.1","v0.9.0","v0.8.9","v0.8.8","v0.8.7","v0.8.6","v0.8.5","v0.8.4","v0.8.3","v0.8.2","v0.8.1","v0.8.0","v0.7.18","v0.7.17","v0.7.16","v0.7.15","v0.7.14","v0.7.13","v0.7.12","v0.7.11","v0.7.10","v0.7.9","v0.7.8","v0.7.7","v0.7.6","v0.7.5","v0.7.4","v0.7.3","v0.7.2","v0.7.1","v0.7.0","v0.6.7","v0.6.6","v0.6.5","v0.6.4","v0.6.3","v0.6.2","v0.6.1","v0.6.0","v0.5.13","v0.5.12","v0.5.11","v0.5.10","v0.5.9","v0.5.8","v0.5.7","v0.5.6","v0.5.5","v0.5.4","v0.5.3","v0.5.2","v0.5.1","v0.5.0","v0.4.2","v0.4.1","v0.4.0","v0.3.3","v0.3.2","v0.3.1","v0.3.0","v0.2.6","v0.2.5","v0.2.4","v0.2.3","v0.2.2","v0.2.1","v0.2.0"],"database_specific":{"source":"https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-45352.json"}}],"schema_version":"1.7.5","severity":[{"type":"CVSS_V3","score":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L"}]}