CVE-2026-40701

MEDIUM

NGINX Plus and NGINX Open Source - Use-After-Free in ngx_http_ssl_module

Title source: llm
STIX 2.1

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.

References (1)

Core 1
Core References
Vendor Advisory vendor-advisory patch
https://my.f5.com/manage/s/article/K000161021

Scores

CVSS v3 4.8
EPSS 0.0004
EPSS Percentile 13.6%
Attack Vector NETWORK
CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:L/I:N/A:L

CISA SSVC

Vulnrichment
Exploitation none
Automatable no
Technical Impact partial

Details

CWE
CWE-416
Status published
Products (5)
F5/NGINX Open Source 1.19.0 - 1.30.1
F5/NGINX Open Source 1.31.0
F5/NGINX Plus R32 - R32 P6
F5/NGINX Plus R36 - R36 P4
F5/NGINX Plus R37
Published May 13, 2026
Tracked Since May 13, 2026