CVE-2026-46527

cpp-httplib is a C++11 single-file header-only cross platform HTTP/HTTPS library. Prior to 0.44.0, When the server has called Server::set_trusted_proxies() with a non-empty trusted-proxy list, an attacker can send an HTTP request that includes an X-Forwarded-For header whose value parses to no valid IP segments. The code path then executes get_client_ip(), which calls front() on an empty std::vector—undefined behavior in C++. On typical implementations this manifests as abnormal process termination (denial of service). With Sanitizers enabled, you get an explicit runtime diagnostic. This vulnerability is fixed in 0.44.0.

CVSS v3 7.5 HIGH

7.5^/10

CVSS v3 : HIGH

Vector :

Exploitability : 3.9 / Impact : 3.6

Attack Vector NETWORK

Attack Complexity LOW

Privileges Required NONE

User Interaction NONE

Confidentiality Impact NONE

Integrity Impact NONE

Availability Impact HIGH

Scope UNCHANGED

References

Link	Resource
https://github.com/yhirose/cpp-httplib/security/advisories/GHSA-hg3g-vrg8-578g	Exploit Mitigation Vendor Advisory
https://github.com/yhirose/cpp-httplib/security/advisories/GHSA-hg3g-vrg8-578g	Exploit Mitigation Vendor Advisory

Configurations

Configuration 1 (hide)

cpe:2.3:a:yhirose:cpp-httplib:*:*:*:*:*:*:*:*

History

No history.

Information

Published : 2026-05-29 20:16

Updated : 2026-07-22 06:10

NVD link : CVE-2026-46527

Mitre link : CVE-2026-46527

CVE.ORG link : CVE-2026-46527

JSON object : View

Products Affected

yhirose

cpp-httplib

CWE

CWE-476

NULL Pointer Dereference

{"id": "CVE-2026-46527", "cveTags": [], "metrics": {"ssvcV203": [{"source": "134c704f-9b21-4f2e-91b3-4a467353bcc0", "ssvcData": {"id": "CVE-2026-46527", "role": "CISA Coordinator", "options": [{"exploitation": "poc"}, {"automatable": "no"}, {"technicalImpact": "partial"}], "version": "2.0.3", "timestamp": "2026-06-01T13:52:10.500850Z"}}], "cvssMetricV31": [{"type": "Primary", "source": "nvd@nist.gov", "cvssData": {"scope": "UNCHANGED", "version": "3.1", "baseScore": 7.5, "attackVector": "NETWORK", "baseSeverity": "HIGH", "vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H", "integrityImpact": "NONE", "userInteraction": "NONE", "attackComplexity": "LOW", "availabilityImpact": "HIGH", "privilegesRequired": "NONE", "confidentialityImpact": "NONE"}, "impactScore": 3.6, "exploitabilityScore": 3.9}], "cvssMetricV40": [{"type": "Secondary", "source": "security-advisories@github.com", "cvssData": {"Safety": "NOT_DEFINED", "version": "4.0", "Recovery": "NOT_DEFINED", "baseScore": 8.7, "Automatable": "NOT_DEFINED", "attackVector": "NETWORK", "baseSeverity": "HIGH", "valueDensity": "NOT_DEFINED", "vectorString": "CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X", "exploitMaturity": "NOT_DEFINED", "providerUrgency": "NOT_DEFINED", "userInteraction": "NONE", "attackComplexity": "LOW", "attackRequirements": "NONE", "privilegesRequired": "NONE", "subIntegrityImpact": "NONE", "vulnIntegrityImpact": "NONE", "integrityRequirement": "NOT_DEFINED", "modifiedAttackVector": "NOT_DEFINED", "subAvailabilityImpact": "NONE", "vulnAvailabilityImpact": "HIGH", "availabilityRequirement": "NOT_DEFINED", "modifiedUserInteraction": "NOT_DEFINED", "modifiedAttackComplexity": "NOT_DEFINED", "subConfidentialityImpact": "NONE", "vulnConfidentialityImpact": "NONE", "confidentialityRequirement": "NOT_DEFINED", "modifiedAttackRequirements": "NOT_DEFINED", "modifiedPrivilegesRequired": "NOT_DEFINED", "modifiedSubIntegrityImpact": "NOT_DEFINED", "modifiedVulnIntegrityImpact": "NOT_DEFINED", "vulnerabilityResponseEffort": "NOT_DEFINED", "modifiedSubAvailabilityImpact": "NOT_DEFINED", "modifiedVulnAvailabilityImpact": "NOT_DEFINED", "modifiedSubConfidentialityImpact": "NOT_DEFINED", "modifiedVulnConfidentialityImpact": "NOT_DEFINED"}}]}, "affected": [{"source": "security-advisories@github.com", "affectedData": [{"vendor": "yhirose", "product": "cpp-httplib", "versions": [{"status": "affected", "version": "< 0.44.0"}]}]}], "published": "2026-05-29T20:16:28.137", "references": [{"url": "https://github.com/yhirose/cpp-httplib/security/advisories/GHSA-hg3g-vrg8-578g", "tags": ["Exploit", "Mitigation", "Vendor Advisory"], "source": "security-advisories@github.com"}, {"url": "https://github.com/yhirose/cpp-httplib/security/advisories/GHSA-hg3g-vrg8-578g", "tags": ["Exploit", "Mitigation", "Vendor Advisory"], "source": "134c704f-9b21-4f2e-91b3-4a467353bcc0"}], "vulnStatus": "Analyzed", "weaknesses": [{"type": "Secondary", "source": "security-advisories@github.com", "description": [{"lang": "en", "value": "CWE-476"}]}], "descriptions": [{"lang": "en", "value": "cpp-httplib is a C++11 single-file header-only cross platform HTTP/HTTPS library. Prior to 0.44.0, When the server has called Server::set_trusted_proxies() with a non-empty trusted-proxy list, an attacker can send an HTTP request that includes an X-Forwarded-For header whose value parses to no valid IP segments. The code path then executes get_client_ip(), which calls front() on an empty std::vector\u2014undefined behavior in C++. On typical implementations this manifests as abnormal process termination (denial of service). With Sanitizers enabled, you get an explicit runtime diagnostic. This vulnerability is fixed in 0.44.0."}, {"lang": "es", "value": "cpp-httplib es una biblioteca HTTP/HTTPS multiplataforma de un solo archivo de cabecera C++11. Antes de 0.44.0, cuando el servidor ha llamado a Server::set_trusted_proxies() con una lista de proxies de confianza no vac\u00eda, un atacante puede enviar una solicitud HTTP que incluye una cabecera X-Forwarded-For cuyo valor se analiza como ning\u00fan segmento IP v\u00e1lido. La ruta del c\u00f3digo entonces ejecuta get_client_ip(), que llama a front() en un std::vector vac\u00edo -comportamiento indefinido en C++. En implementaciones t\u00edpicas, esto se manifiesta como terminaci\u00f3n anormal del proceso (denegaci\u00f3n de servicio). Con los Sanitizers habilitados, se obtiene un diagn\u00f3stico expl\u00edcito en tiempo de ejecuci\u00f3n. Esta vulnerabilidad est\u00e1 corregida en 0.44.0."}], "lastModified": "2026-07-22T06:10:00.170", "configurations": [{"nodes": [{"negate": false, "cpeMatch": [{"criteria": "cpe:2.3:a:yhirose:cpp-httplib:*:*:*:*:*:*:*:*", "vulnerable": true, "matchCriteriaId": "80135DFE-EACD-44FD-990F-0239F78D0518", "versionEndExcluding": "0.44.0"}], "operator": "OR"}]}], "sourceIdentifier": "security-advisories@github.com"}