Uncontrolled resource consumption in yhirose cpp-httplib
Key facts
- Attack vector
- Network
- Privileges required
- None
- User interaction
- None
- Attack complexity
- Low
- Impact type
- Denial of service
- Confidentiality · integrity · availability
- None · None · High
- Fix status
- Fixed
Attack profile from CVSS 3.1 · CNA. Fix status from CNA. Impact type from CWE-400.
Summary
cpp-httplib is a C++11 single-file header-only cross platform HTTP/HTTPS library. Prior to 0.35.0, cpp-httplib (httplib.h) does not enforce Server::set_payload_max_length() on the decompressed request body when using HandlerWithContentReader (streaming ContentReader) with Content-Encoding: gzip (or other supported encodings). A small compressed payload can expand beyond the configured payload limit and be processed by the application, enabling a payload size limit bypass and potential denial of service (CPU/memory exhaustion). This vulnerability is fixed in 0.35.0.
Why it matters now
SSVC decision points
CISA ADP · SSVC 2.0.3
- Exploitation
- Poc
- Automatable
- Yes
- Technical impact
- Partial
The decision (Track, Attend, Act) also depends on your mission and well-being impact; see CISA's SSVC guide.
Affected products
Remediation
- Fix · CNA cpp-httplib (yhirose) Fixed in 0.35.0
Vendor assessments
Timeline
- 2026-10-02 Threatist record created from CVE-2026-28435
References
More yhirose Cpp-httplib vulnerabilities
- TI-2026-33163 cpp-httplib: HTTP header value percent-decoding in server-side `parse_header` enables CRLF injection CVSS 3.1CRITICAL 9.9
- TI-2026-18294 cpp-httplib vulnerable to a denial of service (DOS) using a zip bomb CVSS 4.0HIGH 8.7
- TI-2026-17313 cpp-httplib has CRLF injection in http headers CVSS 4.0HIGH 7.7
- TI-2026-33146 cpp-httplib DoS: Negative chunk-size in chunked Transfer-Encoding CVSS 3.1HIGH 7.5
- TI-2025-33556 cpp-httplib Unbounded Memory Allocation in Chunked/No-Length Requests Vulnerability CVSS 3.1HIGH 7.5
- TI-2025-32923 cpp-httplib has unlimited number of http header fields, which causes memory leak CVSS 3.1HIGH 7.5
Sources
- CVE-2026-28435 · CVE Program
- CVE-2026-28435 · NVD
- FIRST EPSS
- CVE-2026-28435 · Red Hat security data · CC BY 4.0
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