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.
Affected products
| Vendor | Product | Affected | Fixed |
|---|---|---|---|
| F5 | NGINX Open Source | 1.29.0 – < 1.29.7, 0.6.27 – < 1.28.3 | 1.29.7 |
| F5 | NGINX Plus | R36 – < R36 P3, R35 – < R35 P2, R34, R33, R32 – < R32 P5 | R36 P3 |
Fixed in Linux distributions
Distributions backport fixes, so the version that fixes this vulnerability differs per release — upgrade to at least the version shown. From the distributions' security trackers and advisories.
Debian
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Debian 14 | nginx | 1.28.3-1 | — |
| Debian 13 | nginx | 1.26.3-3+deb13u3 | — |
| Debian 12 | nginx | 1.22.1-9+deb12u5 | — |
Ubuntu
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Ubuntu 25.10 | nginx | 1.28.0-6ubuntu1.2 | — |
| Ubuntu 24.04 LTS | nginx | 1.24.0-2ubuntu7.7 | — |
| Ubuntu 22.04 LTS | nginx | 1.18.0-6ubuntu14.10 | — |
Show 4 more (older releases, extended support, other products)Fewer releases
| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Ubuntu Pro 20.04 LTS | nginx | 1.18.0-0ubuntu1.7+esm1 | — |
| Ubuntu Pro 18.04 LTS | nginx | 1.14.0-0ubuntu1.11+esm2 | — |
| Ubuntu Pro 16.04 LTS | nginx | 1.10.3-0ubuntu0.16.04.5+esm7 | — |
| Ubuntu Pro 14.04 LTS | nginx | 1.4.6-1ubuntu3.9+esm6 | — |
Red Hat
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Red Hat Hardened Images 1 | nginx +11 | 1.30.0-1.hum1 | RHSA-2026:8346 |
openSUSE
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| openSUSE Tumbleweed | nginx | 1.29.7-1.1 | openSUSE-SU-2026:10423-1 |
Alpine
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Alpine v3.24 | nginx | 1.28.3-r0 | — |
| Alpine v3.23 | nginx | 1.28.3-r0 | — |
| Alpine v3.22 | nginx | 1.28.3-r0 | — |
Amazon Linux
| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Amazon Linux 2023 | nginx +9 | 1:1.28.3-1.amzn2023.0.1 | ALAS2023-2026-1540 |
Azure Linux
| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Azure Linux 3 | nginx | 1.28.3-1 | — |
Wolfi
| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Wolfi rolling | nginx-mainline | 1.29.7-r0 | — |
| Wolfi rolling | nginx-stable | 1.28.3-r0 | — |
Advisories 5
- WID-SEC-2026-0860 NGINX und NGINX Plus: Mehrere Schwachstellen BSI CERT-Bund (WID) · Nov 11, 2026
- WID-SEC-2026-2933 Splunk SOAR: Mehrere Schwachstellen BSI CERT-Bund (WID) · Nov 2, 2026
- RHSA-2026:8346 Red Hat Security Advisory: Red Hat Hardened Images RPMs bug fix and enhancement update Red Hat Security Advisories (RHSA) · Oct 10, 2026
- ALAS2023-2026-1540 Important: nginx security update (Amazon Linux 2023) Amazon Linux Security Center (ALAS) · Apr 13, 2026
- openSUSE-SU-2026:10423-1 nginx-1.29.7-1.1 on GA media SUSE / openSUSE Security Updates · Mar 26, 2026
References
- https://my.f5.com/manage/s/article/K000160367 vendor-advisory