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. 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.
Published:Mar 24, 2026
Last Modified:Mar 27, 2026
EPS:Mar 24, 2026
EPSS Score:0.00017
CVSS Score:3.7
Affected Products
Vendor
Product
Action
Vendor
F5
Product
Nginx Open Source
F5
Nginx Open Source
Vendor
F5
Product
Nginx Plus
F5
Nginx Plus
Exploits
No exploit reference
Common Weakness Enumeration
Common Attack Pattern Enumeration and Classification (CAPEC)
Related CVEs
Common Vulnerability Scoring System
Attack Vector
Network
Adjacent
Local
Physical
Privileges Required
None
Low
High
User Interaction
None
Required
Scope
Unchanged
Changed
Confidentiality
None
Low
High
Integrity
None
Low
High
Availability
None
Low
High
