NULL pointer dereference in ESP-IDF - CVE-2026-45541
Published: May 16, 2026
Vulnerability identifier: #VU131603
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-2026-45541
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 null pointer dereference in httpd_ws_get_response_subprotocol() in the esp_http_server component when parsing the client-supplied Sec-WebSocket-Protocol header during the WebSocket handshake. A remote attacker can send a malformed header value to cause a denial of service.
The issue is reachable only when WebSocket support is enabled and at least one registered WebSocket URI handler performs subprotocol negotiation by supplying a non-NULL supported_subprotocol.
Affected software
ESP-IDF
How to mitigate CVE-2026-45541
Install security update from vendor's website.
ESP-IDF - update to 6.0.1