CVE-2026-28753: NGINX ngx_mail_proxy_module vulnerability
Last updated 6 June 2026
Other sources
NGINX ngxmailproxymodule vulnerability
— Microsoft
NGINX Plus and NGINX Open Source have a vulnerability in the ngxmailsmtpmodule 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.
— F5
Affected Software
Event History
Frequently Asked Questions
What is the severity of CVE-2026-28753?
CVE-2026-28753 has been classified as a high severity vulnerability due to its potential to allow arbitrary header injection.
How do I fix CVE-2026-28753?
To fix CVE-2026-28753, users should upgrade to the latest versions of NGINX Plus or NGINX Open Source as specified in the vendor's security advisory.
What are the affected versions for CVE-2026-28753?
CVE-2026-28753 affects NGINX Plus and NGINX Open Source versions prior to their respective patched releases.
What type of attack is associated with CVE-2026-28753?
CVE-2026-28753 allows an attacker to exploit DNS responses to inject malicious headers during SMTP upstream requests.
Is CVE-2026-28753 remotely exploitable?
Yes, CVE-2026-28753 is remotely exploitable, making it critical to address for affected systems.