CVE-2026-27651
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Awaiting Analysis - Queue
Denial of Service in NGINX ngx_mail_auth_http_module via Auth-Wait
Publication date: 2026-03-24
Last updated on: 2026-03-30
Assigner: F5 Networks
Description
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.
CVSS Scores
EPSS Scores
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Meta Information
Affected Vendors & Products
| Vendor | Product | Version / Range |
|---|---|---|
| f5 | nginx_plus | r32 |
| f5 | nginx_plus | r32 |
| f5 | nginx_plus | r32 |
| f5 | nginx_plus | r32 |
| f5 | nginx_plus | r35 |
| f5 | nginx_plus | r36 |
| f5 | nginx_plus | r36 |
| f5 | nginx_plus | From r33 (inc) to r35 (exc) |
| f5 | nginx_plus | r35 |
| f5 | nginx_plus | r36 |
| f5 | nginx_open_source | From 1.29.0 (inc) to 1.29.7 (exc) |
| f5 | nginx_plus | r32 |
| f5 | nginx_open_source | From 1.0.0 (inc) to 1.28.3 (exc) |
| f5 | nginx_open_source | From 0.5.15 (inc) to 0.9.7 (inc) |
Helpful Resources
Exploitability
CWE
KEV
| CWE ID | Description |
|---|---|
| CWE-476 | The product dereferences a pointer that it expects to be valid but is NULL. |
