Quick answers
- Is CVE-2026-45352 exploited in the wild?
- No. Junglewise Threat Intelligence has no report of CVE-2026-45352 being exploited in the wild.
- How severe is CVE-2026-45352?
- Medium severity, with a CVSS score of 5.3, published 29 May 2026.
- Which products and versions are affected?
- Yhirose Cpp-Httplib < 0.43.4.
- Is there a fix for CVE-2026-45352?
- No fixed version is recorded yet. Check the vendor's advisory in the references below. If you run it, Junglewise drafts a mitigation that fits your setup and applies it once you approve, with senior security engineers behind it.
- How is CVE-2026-45352 attacked?
- It is attacked over the network, in a software library.
- Am I affected by CVE-2026-45352?
- Check whether you run Yhirose Cpp-Httplib at an affected version. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.
Technical details
The ChunkedDecoder::read_payload function in httplib.h uses std::strtoul() to parse the chunk-size field of HTTP chunked transfer encoding. Because strtoul() performs unsigned wrap-around for negative inputs, a value such as '-2' is interpreted as a near-maximum unsigned long value (e.g., 0xFFFFFFFFFFFFFFFE). While the library explicitly checks for and rejects ULONG_MAX (the result of '-1'), it fails to validate other negative inputs. This causes the server to enter a read loop attempting to consume an extremely large amount of data, leading to unbounded memory allocation (std::bad_alloc) and a process crash. The vulnerability is fixed in version 0.43.4 by ensuring the parser correctly rejects non-hexadecimal characters like the leading minus sign.
Affected products
- yhirose cpp-httplib < 0.43.4
Timeline
- 2026-05-12: advisory: GitHub Security Advisory published
- 2026-05-29: disclosed: CVE-2026-45352 published to NVD