CVE-2026-45352— cpp-httplib DoS: Negative chunk-size in chunked Transfer-Encoding
Possible ATT&CK Techniques 2AI
T1190 · Exploit Public-Facing Application T1210 · Exploitation of Remote ServicesAffected Version Matrix 1
| Vendor | Product | Version Range | Status |
|---|---|---|---|
| yhirose | cpp-httplib | < 0.43.4 | affected |
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I. Basic Information for CVE-2026-45352
Vulnerability Information
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Vulnerability Title
cpp-httplib DoS: Negative chunk-size in chunked Transfer-Encoding
Source: NVD (National Vulnerability Database)
Vulnerability Description
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.
Source: NVD (National Vulnerability Database)
CVSS Information
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L
Source: NVD (National Vulnerability Database)
Vulnerability Type
输入验证不恰当
Source: NVD (National Vulnerability Database)
Affected Products
| Vendor | Product | Affected Versions | CPE | Subscribe |
|---|---|---|---|---|
| yhirose | cpp-httplib | < 0.43.4 | - |
II. Public POCs for CVE-2026-45352
| # | POC Description | Source Link | Shenlong Link |
|---|
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Vendor Advisories for CVE-2026-45352 (1)
Same Patch Batch · yhirose · 2026-05-29 · 3 CVEs total
| CVE-2026-45372 | 9.9 CRITICAL | cpp-httplib: HTTP header value percent-decoding in server-side `parse_header` enables CRLF |
| CVE-2026-46527 | cpp-httplib: Malicious `X-Forwarded-For` Under Trusted-Proxy Configuration Triggers Empty |
IV. Related Vulnerabilities
Same product: cpp-httplib
- CVE-2026-45372
cpp-httplib: HTTP header value percent-decoding in server-si - CVE-2026-46527
cpp-httplib: Malicious `X-Forwarded-For` Under Trusted-Proxy - CVE-2026-34441
cpp-httplib: HTTP Request Smuggling via Unconsumed GET Reque - CVE-2026-33745
cpp-httplib Client Leaks Authentication Credentials to Untru - CVE-2026-32627
cpp-httplib has a Silent TLS Certificate Verification Bypass
Same vendor: yhirose
- CVE-2026-45372
cpp-httplib: HTTP header value percent-decoding in server-si - CVE-2026-46527
cpp-httplib: Malicious `X-Forwarded-For` Under Trusted-Proxy - CVE-2026-34441
cpp-httplib: HTTP Request Smuggling via Unconsumed GET Reque - CVE-2026-33745
cpp-httplib Client Leaks Authentication Credentials to Untru - CVE-2026-32627
cpp-httplib has a Silent TLS Certificate Verification Bypass
Same weakness: CWE-20
V. Comments for CVE-2026-45352
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