NULL pointer dereference in Cpp-httplib - CVE-2026-46527
Published: May 16, 2026
Vulnerability identifier: #VU131593
CSH Severity: Medium
CVSS v4.0: 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:U/U:Green
CVE-ID: CVE-2026-46527
CWE-ID: CWE-476
Exploitation vector: Remote access
Exploit availability:
No public exploit available
Vendor: Cpp-httplib Project
Affected software:
Cpp-httplib
Cpp-httplib
Detailed vulnerability description
The vulnerability allows a remote attacker to cause a denial of service.
The vulnerability exists due to undefined behavior from calling front() on an empty std::vector in get_client_ip() when handling HTTP requests with a crafted X-Forwarded-For header under trusted-proxy configuration. A remote attacker can send a specially crafted request to cause a denial of service.
Only deployments that configure a non-empty trusted-proxy list are vulnerable.
How to mitigate CVE-2026-46527
Install security update from vendor's website.