{"id":"UBUNTU-CVE-2026-45352","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.","modified":"2026-06-25T13:30:08.445288395Z","published":"2026-05-29T20:16:00Z","upstream":["CVE-2026-45352"],"references":[{"type":"REPORT","url":"https://ubuntu.com/security/CVE-2026-45352"},{"type":"REPORT","url":"https://www.cve.org/CVERecord?id=CVE-2026-45352"},{"type":"REPORT","url":"https://github.com/yhirose/cpp-httplib/security/advisories/GHSA-h6wq-j5mv-f3q8"}],"affected":[{"package":{"name":"cpp-httplib","ecosystem":"Ubuntu:Pro:22.04:LTS","purl":"pkg:deb/ubuntu/cpp-httplib?arch=source&distro=esm-apps%2Fjammy"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"}]}],"versions":["0.9.9+ds-1","0.9.10+ds-1","0.10.1+ds-1","0.10.2+ds-1","0.10.3+ds-1","0.10.3+ds-1ubuntu0.1~esm1","0.10.3+ds-1ubuntu0.1~esm2"],"ecosystem_specific":{"binaries":[{"binary_version":"0.10.3+ds-1ubuntu0.1~esm2","binary_name":"libcpp-httplib0"}]},"database_specific":{"source":"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-45352.json"}},{"package":{"name":"cpp-httplib","ecosystem":"Ubuntu:Pro:24.04:LTS","purl":"pkg:deb/ubuntu/cpp-httplib?arch=source&distro=esm-apps%2Fnoble"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"}]}],"versions":["0.13.1+ds-1ubuntu1","0.14.3+ds-1","0.14.3+ds-1.1","0.14.3+ds-1.1build1","0.14.3+ds-1.1build2","0.14.3+ds-1.1ubuntu0.1~esm1","0.14.3+ds-1.1ubuntu0.1~esm2"],"ecosystem_specific":{"binaries":[{"binary_version":"0.14.3+ds-1.1ubuntu0.1~esm2","binary_name":"libcpp-httplib0.14t64"}]},"database_specific":{"source":"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-45352.json"}},{"package":{"name":"cpp-httplib","ecosystem":"Ubuntu:25.10","purl":"pkg:deb/ubuntu/cpp-httplib?arch=source&distro=questing"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"}]}],"versions":["0.18.7-1","0.18.7-1ubuntu0.25.10.1","0.18.7-1ubuntu0.25.10.2"],"ecosystem_specific":{"binaries":[{"binary_name":"libcpp-httplib0.18","binary_version":"0.18.7-1ubuntu0.25.10.2"}]},"database_specific":{"source":"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-45352.json"}},{"package":{"name":"cpp-httplib","ecosystem":"Ubuntu:Pro:26.04:LTS","purl":"pkg:deb/ubuntu/cpp-httplib?arch=source&distro=esm-apps%2Fresolute"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"}]}],"versions":["0.18.7-1","0.26.0+ds-2ubuntu2","0.26.0+ds-2ubuntu3","0.26.0+ds-2ubuntu3+esm1"],"ecosystem_specific":{"binaries":[{"binary_name":"libcpp-httplib0.26","binary_version":"0.26.0+ds-2ubuntu3+esm1"}]},"database_specific":{"source":"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-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"},{"type":"CVSS_V3","score":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H"},{"type":"Ubuntu","score":"medium"}]}