Unrated severityNVD Advisory· Published Mar 24, 2026· Updated Mar 24, 2026
NGINX ngx_mail_auth_http_module vulnerability
CVE-2026-27651
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.
Affected products
1- Range: R36
Patches
0No patches discovered yet.
Vulnerability mechanics
AI mechanics synthesis has not run for this CVE yet.
References
1- my.f5.com/manage/s/article/K000160383mitrevendor-advisory
News mentions
2- PoC Code Published for Critical NGINX VulnerabilitySecurityWeek · May 16, 2026
- 18-Year-Old NGINX Rewrite Module Flaw Enables Unauthenticated RCEThe Hacker News · May 14, 2026