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LOW · 3.7

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. This allows an attacker-controlled DNS server ...

Vulnerability 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.

CVSS Score

3.7

LOW

CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:L/A:N
Attack Vector
NETWORK
Attack Complexity
HIGH
Privileges Required
NONE
User Interaction
NONE
Scope
UNCHANGED
Confidentiality
NONE
Integrity
LOW
Availability
NONE

Affected Products

VendorProductVersions
F5Nginx Plusr32
F5Nginx Open Source>= 0.6.27, <= 0.9.7

Related Weaknesses (CWE)

CWE-93

References

FAQ

What is CVE-2026-28753?

CVE-2026-28753 is a vulnerability with a CVSS score of 3.7 (LOW). 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 ...

How severe is CVE-2026-28753?

CVE-2026-28753 has been rated LOW with a CVSS base score of 3.7/10. Review the CVSS metrics above for detailed severity breakdown.

Is there a patch for CVE-2026-28753?

Check the references section above for vendor advisories and patch information. Affected products include: F5 Nginx Plus, F5 Nginx Open Source.