CVE-2026-40701 MEDIUM

CVE-2026-40701: NGINX ngx_http_ssl_module vulnerability

Vendor F5
Product NGINX Plus
Weakness CWE-416
Published May 13, 2026
Last update May 13, 2026

CVSS base score

4.8/10
Attack vector Network
Attack complexity High
Privileges required None
User interaction None
Confidentiality Low
Integrity None

CVSS vector

CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:L/I:N/A:L

What the vulnerability does

Description

NGINX Plus and NGINX Open Source have a vulnerability in the ngx_http_ssl_module module when the ssl_verify_client directive is set to "on" or "optional," and the ssl_ocsp directive is set to "on" or the leaf parameters are configured with a resolver. With this configuration, an unauthenticated attacker can send requests along with conditions beyond its control that may cause a heap-use-after-free error in the NGINX worker process. This vulnerability may result in limited modification of data or the NGINX worker process restarting.  Note: Software versions which have reached End of Technical Support (EoTS) are not evaluated.

Key dates

Disclosure timeline

May 13, 2026 CVE published
May 13, 2026 Record updated