CVE-2026-27651 HIGH

CVE-2026-27651: NGINX ngx_mail_auth_http_module vulnerability

Vendor F5
Product NGINX Open Source
Weakness CWE-476
Published March 24, 2026
Last update March 24, 2026
View on NVD All CVEs

CVSS base score

7.5/10
Attack vector Network
Attack complexity Low
Privileges required None
User interaction None
Confidentiality None
Integrity None

CVSS vector

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

What the vulnerability does

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.

Key dates

Disclosure timeline

March 24, 2026 CVE published
March 24, 2026 Record updated