CVE-2026-27651

HIGH

NGINX ngx_mail_auth_http_module vulnerability

Title source: cna
STIX 2.1

Description

When the ngx_mail_auth_http_module module is enabled on NGINX Plus or NGINX Open Source, undisclosed requests can cause worker processes to terminate. This issue may occur when (1) CRAM-MD5 or APOP authentication is enabled, and (2) the authentication server permits retry by returning the Auth-Wait response header. Note: Software versions which have reached End of Technical Support (EoTS) are not evaluated.

Scores

CVSS v3 7.5
EPSS 0.0004
EPSS Percentile 13.6%
Attack Vector NETWORK
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

CISA SSVC

Vulnrichment
Exploitation none
Automatable yes
Technical Impact partial

Details

CWE
CWE-476
Status published
Products (12)
F5/NGINX Open Source 0.5.15 - 1.28.3
F5/NGINX Open Source 1.29.0 - 1.29.7
F5/NGINX Plus R32 - R32 P5
F5/NGINX Plus R33
F5/NGINX Plus R34
F5/NGINX Plus R35 - R35 P2
F5/NGINX Plus R36 - R36 P3
f5/nginx_open_source 0.5.15 - 0.9.7
f5/nginx_plus r32 (5 CPE variants)
f5/nginx_plus r35 (2 CPE variants)
... and 2 more
Published Mar 24, 2026
Tracked Since Mar 24, 2026