CVE-2026-28753
NGINX ngx_mail_proxy_module vulnerability
3.7
LOW
CVSS 3.1
EPSS 0.03%
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.
How to fix CVE-2026-28753
To remediate CVE-2026-28753, upgrade the affected package to a fixed version below.
- —upgrade to 1.28.3-r0 or later
- —upgrade to 1.28.3 or later
- —upgrade to 1.28.3 or later
- —upgrade to 1.18.0-6.1+deb11u6 or later
Is CVE-2026-28753 being exploited?
Low — EPSS is 0.0%, meaning exploitation activity has not been observed at scale.
Affected packages (4)
- from 0, < 1.28.3-r0
- >= 0.6.27, < 1.28.3, >= 1.29.0, < 1.29.7
- >= 0.6.27, < 1.28.3, >= 1.29.0, < 1.29.7
- from 0, < 1.18.0-6.1+deb11u6
CVSS scores
| Source | Version | Severity | Vector |
|---|---|---|---|
| osv | CVSS 4.0 | — | CVSS:4.0/AV:N/AC:H/AT:P/PR:N/UI:N/VC:N/VI:L/VA:N/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X |
| osv | CVSS 3.1 | LOW3.7 | CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:L/A:N |