low3.7
CVE-2026-28753
NGINX Plus and NGINX Open Source have a vulnerability in the ngx_mail_smtp_module module due to the improper handling of CRLF sequences in DNS responses.
Impact
NGINX Plus and NGINX Open Source have a vulnerability in the ngx_mail_smtp_module module due to the improper handling of CRLF sequences in DNS responses. This allows an attacker-controlled DNS server to inject arbitrary headers into SMTP upstream requests, leading to potential request manipulation. Note: Software versions which have reached End of Technical Support (EoTS) are not evaluated.
Affected products
| Vendor | Product | Affected versions |
|---|---|---|
| F5 | Nginx Plus | Versions r32, r33, r34, r35, r36 |
| F5 | Nginx Open Source | from 0.6.27 through 0.9.7 from 1.0.0 before 1.28.3 from 1.29.0 before 1.29.7 |