Buffer overflow in libwebsockets - CVE-2025-1866
Published: November 3, 2025
Vulnerability identifier: #VU117944
CSH Severity: Medium
CVSS v4.0: CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:A/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N/E:U/U:Green
CVE-ID: CVE-2025-1866
CWE-ID: CWE-119
Exploitation vector: Remote access
Exploit availability:
No public exploit available
Vendor: libwebsockets.org
Affected software:
libwebsockets
libwebsockets
Detailed vulnerability description
The vulnerability allows a remote attacker to execute arbitrary code on the target system.
The vulnerability exists due to a boundary error in win32port/zlib/inftrees.c. A remote attacker can trigger memory corruption and execute arbitrary code on the target system.
Successful exploitation of this vulnerability requires that the code is built specifically for the Win32 platform with specific compiler options.
How to mitigate CVE-2025-1866
Install updates from vendor's website.