NULL pointer dereference in Cpp-httplib - CVE-2026-46527
Published: May 16, 2026
Vulnerability identifier: #VU131593
CSH Severity: Medium
CVSS v4: 8.7 [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]
CVE-ID: CVE-2026-46527
CWE-ID: CWE-476
Exploitation vector: Remote access
Exploit availability:
No public exploit available
Vulnerability details
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.
Affected software
Cpp-httplib
Fedora
openEuler
cpp-httplib
cpp-httplib-debuginfo
cpp-httplib-debugsource
cpp-httplib-devel
Fedora
openEuler
cpp-httplib
cpp-httplib-debuginfo
cpp-httplib-debugsource
cpp-httplib-devel
How to mitigate CVE-2026-46527
Install security update from vendor's website.
Cpp-httplib - update to 0.44.0
cpp-httplib - update to 0.46.0-1
cpp-httplib-debuginfo - update to 0.46.0-1
cpp-httplib-debugsource - update to 0.46.0-1
cpp-httplib-devel - update to 0.46.0-1
cpp-httplib - addressed in versions 0.48.0-1.el9, 0.48.0-1.el10_3, 0.48.0-1.fc43, 0.48.0-1.fc44
cpp-httplib - update to 0.46.0-1
cpp-httplib-debuginfo - update to 0.46.0-1
cpp-httplib-debugsource - update to 0.46.0-1
cpp-httplib-devel - update to 0.46.0-1
cpp-httplib - addressed in versions 0.48.0-1.el9, 0.48.0-1.el10_3, 0.48.0-1.fc43, 0.48.0-1.fc44