Cpp Httplib
CVE-2026-29076
MEDIUM
Vulnerability Assessment
| Weakness |
CWE
OWASP Top 10:2025
A06:2021 - Vulnerable and Outdated Components
ASVS 5.0
V15 - Secure Coding and Architecture Recursion depth limits
|
| Impact | CVSS 5.9 (MEDIUM). Attack vector: Network. Complexity: High. Privileges required: None. User interaction: None. Public exploit/POC available. |
| Exploit ScenarioDerived | An attacker could exploit this flaw, a stack overflow (SIGSEGV) that crashes the server process. |
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Alert meAnalysisAIv1 – Mar 12, 2026
Remote denial of service in cpp-httplib prior to version 0.37.0 allows unauthenticated attackers to crash server processes by submitting HTTP POST requests with maliciously crafted RFC 5987 filename* parameters that trigger catastrophic backtracking in the regex parser. The vulnerability exploits the recursive stack-based implementation of libstdc++'s regex engine, causing uncontrolled stack growth and stack overflow. Public exploit code exists for this vulnerability.
Earlier versions of this analysis (1)
cpp-httplib is a C++11 single-file header-only cross platform HTTP/HTTPS library. Prior to version 0.37.0, cpp-httplib uses std::regex (libstdc++) to parse RFC 5987 encoded filename* values in multipart Content-Disposition headers. [CVSS 5.9 MEDIUM]
RemediationAI
A vendor patch is available — apply it immediately. Fixed in version 0.37.0.. Restrict network access to the affected service where possible.
Affects your stack
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Technical ContextAI · show details
Classified as CWE-674 (Uncontrolled Recursion). Affects Cpp-Httplib. cpp-httplib is a C++11 single-file header-only cross platform HTTP/HTTPS library. Prior to version 0.37.0, cpp-httplib uses std::regex (libstdc++) to parse RFC 5987 encoded filename* values in multipart Content-Disposition headers. The regex engine in libstdc++ implements backtracking via deep recursion, consuming one stack frame per input character. An attacker can send a single HTTP POST request with a crafted filename* parameter that causes uncontrolled stack growth, resulting in a stack over
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- Exploit and PoC references, threat intelligence from 22 sources
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Severity by source
AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H
Primary rating from GitHub Advisory.
CVSS VectorGitHub Advisory
Lifecycle Timeline
3DescriptionGitHub Advisory
cpp-httplib is a C++11 single-file header-only cross platform HTTP/HTTPS library. Prior to version 0.37.0, cpp-httplib uses std::regex (libstdc++) to parse RFC 5987 encoded filename* values in multipart Content-Disposition headers. The regex engine in libstdc++ implements backtracking via deep recursion, consuming one stack frame per input character. An attacker can send a single HTTP POST request with a crafted filename* parameter that causes uncontrolled stack growth, resulting in a stack overflow (SIGSEGV) that crashes the server process. This issue has been patched in version 0.37.0.
Executive ViewAI
Organizations using cpp-httplib should be aware of moderate risk from CVE-2026-29076 rated CVSS 5.9. Exploitation could compromise the security of affected deployments. Proof-of-concept code is publicly available. A patch is available and should be applied during regular vulnerability management.
Apply vendor patch. If patching is delayed: restrict network access and enable monitoring.
Threat Intelligence Overview
NVD
CVE.org
EPSS
GitHub
How this decision was reached
The engine reads each signal below and applies a fixed list of rules from top to bottom. The first rule that matches sets the recommended action – like a statement, every line is shown.
What every action level means
SSVC AssessmentENISA
Priority Score
Attack Technique
A stack-based buffer overflow occurs when a program writes more data to a buffer located on the stack than it was allocated to hold.
Denial of Service attacks render applications or systems unavailable by overwhelming resources or triggering failure conditions.
Affected Products (CPE)GitHub Advisory
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Same weakness CWE-674 – Uncontrolled Recursion
View allSame technique Denial Of Service
View allVendor StatusVendor
SUSE
Severity: Medium| Product | Status |
|---|---|
| openSUSE Tumbleweed | Fixed |
| SUSE Linux Enterprise Server 16.1 | Fixed |
| SUSE Linux Enterprise Server for SAP applications 16.1 | Fixed |
Exploit-DB