CVE-2026-28753

MEDIUM EPSS 17.8%
Published Mar 24, 20263mo ago · Modified Jun 17, 20262w ago
6.3 CVSS 4.0
Medium
Find Similar
Published Mar 24, 2026 3mo ago
Last Modified Jun 17, 2026 2w ago

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 Details

Base Score
6.3
Exploitability
—
Impact
—
Vector string
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
Attack Vector Network
Attack Complexity High
Privileges Required None
User Interaction None
Scope X

Threat Intelligence

EPSS Exploit Probability
17.8% percentile
Exploit & Patch Status
No Known Exploit
No Patch Available

Weaknesses 1

CWE-93

Affected Products 19

VendorProductVersionRange
f5nginx_plusr32any
f5nginx_plusr32any
f5nginx_plusr32any
f5nginx_plusr32any
f5nginx_plusr33any
f5nginx_plusr33any
f5nginx_plusr33any
f5nginx_plusr33any
f5nginx_plusr34any
f5nginx_plusr34any
f5nginx_plusr34any
f5nginx_plusr35any
f5nginx_plusr35any
f5nginx_plusr36any
f5nginx_plusr36any
f5nginx_plusr36any
f5nginx_open_source*≥0.6.27  –  ≤0.9.7
f5nginx_open_source*≥1.0.0  –  <1.28.3
f5nginx_open_source*≥1.29.0  –  <1.29.7

References 1

  • my.f5.com https://my.f5.com/manage/s/article/K000160367
    Vendor Advisory

Remediation

No remediation data recorded yet

Check vendor advisories and the NVD entry for patch availability.