CVE-2026-28753

EUVD-2026-14885
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.
CRLF Injection
ProviderTypeBase ScoreAtk. VectorAtk. ComplexityPriv. RequiredVector
NISTPrimary
3.7 LOW
NETWORK
HIGH
NONE
CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:L/A:N
f5CNA
3.7 LOW
NETWORK
HIGH
NONE
CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:L/A:N
Base Score
CVSS 3.x
EPSS Score
Percentile: Unknown
Affected Products (NVD)
VendorProductVersion
f5nginx_open_source
0.6.27 ≤
𝑥
≤ 0.9.7
f5nginx_open_source
1.0.0 ≤
𝑥
< 1.28.3
f5nginx_open_source
1.29.0 ≤
𝑥
< 1.29.7
𝑥
= Vulnerable software versions
Common Weakness Enumeration
References
https://my.f5.com/manage/s/article/K000160367