CVE-2026-28753

low F5
CVSS v3 Base Score
3.7
CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:L/A:N
EPSS Score
0.0%
Exploitation probability in 30 days
Top 96% most likely to be exploited
Attack Characteristics
Attack Vector
Network
Attack Complexity
High
Privileges Required
None
User Interaction
None
Confidentiality
None
Integrity
Low
Availability
None
Published: March 24, 2026 (50 days ago)
Last Modified: March 26, 2026
Vendor: F5
Source: NVD

Description

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.

CWE

CWE-93

Affected Products

f5 nginx plusf5 nginx open source

References