Vulnerability · Published Mar 24, 2026 · Assigned by f5
CVE-2026-27651NGINX ngx_mail_auth_http_module vulnerability
High 7.5
In plain English
A high-severity null pointer dereference in NGINX Open Source from F5. There are no confirmed reports of exploitation so far. The chance it is exploited in the next 30 days is estimated at 1.0% (higher than 62% of all known vulnerabilities). Fixed versions are available - upgrade the affected package.
Severity (CVSS 3.1)7.5High
Exploit odds (30 days)1.0%top 38.5% of all CVEs
Exploited in the wildNo reportsCISA SSVC: none
Attack toolingNoneno public tooling known
Official description
When the ngx_mail_auth_http_module module is enabled on NGINX Plus or NGINX Open Source, undisclosed requests can cause worker processes to terminate. This issue may occur when (1) CRAM-MD5 or APOP authentication is enabled, and (2) the authentication server permits retry by returning the Auth-Wait response header. Note: Software versions which have reached End of Technical Support (EoTS) are not evaluated.
Affected packages & fixed versions
| Ecosystem | Package | Fixed in | Advisory |
|---|---|---|---|
| AlmaLinux:8 | nginx | 1:1.24.0-3.module_el8.10.0+4159+021b4a2a.alma.1 | ALSA-2026:6907 |
| AlmaLinux:9 | nginx | 2:1.20.1-24.el9_7.2.alma.1 | ALSA-2026:7002 |
| AlmaLinux:9 | nginx | 1:1.24.0-5.module_el9.7.0+220+47ec8b91.2.alma.1 | ALSA-2026:6923 |
| AlmaLinux:9 | nginx | 2:1.26.3-2.module_el9.7.0+223+9cd7031b.1 | ALSA-2026:7343 |
| AlmaLinux:10 | nginx-all-modules | 2:1.26.3-2.el10_1.1 | ALSA-2026:6906 |
| AlmaLinux:8 | nginx-all-modules | 1:1.24.0-3.module_el8.10.0+4159+021b4a2a.alma.1 | ALSA-2026:6907 |
| AlmaLinux:9 | nginx-all-modules | 1:1.24.0-5.module_el9.7.0+220+47ec8b91.2.alma.1 | ALSA-2026:6923 |
| AlmaLinux:9 | nginx-all-modules | 2:1.26.3-2.module_el9.7.0+223+9cd7031b.1 | ALSA-2026:7343 |
| AlmaLinux:9 | nginx-all-modules | 2:1.20.1-24.el9_7.2.alma.1 | ALSA-2026:7002 |
| AlmaLinux:9 | nginx-core | 2:1.26.3-2.module_el9.7.0+223+9cd7031b.1 | ALSA-2026:7343 |
| AlmaLinux:9 | nginx-core | 1:1.24.0-5.module_el9.7.0+220+47ec8b91.2.alma.1 | ALSA-2026:6923 |
| AlmaLinux:9 | nginx-core | 2:1.20.1-24.el9_7.2.alma.1 | ALSA-2026:7002 |
| AlmaLinux:10 | nginx-filesystem | 2:1.26.3-2.el10_1.1 | ALSA-2026:6906 |
| AlmaLinux:8 | nginx-filesystem | 1:1.24.0-3.module_el8.10.0+4159+021b4a2a.alma.1 | ALSA-2026:6907 |
| AlmaLinux:9 | nginx-filesystem | 2:1.26.3-2.module_el9.7.0+223+9cd7031b.1 | ALSA-2026:7343 |
| AlmaLinux:9 | nginx-filesystem | 2:1.20.1-24.el9_7.2.alma.1 | ALSA-2026:7002 |
| AlmaLinux:9 | nginx-filesystem | 1:1.24.0-5.module_el9.7.0+220+47ec8b91.2.alma.1 | ALSA-2026:6923 |
| AlmaLinux:8 | nginx-mod-devel | 1:1.24.0-3.module_el8.10.0+4159+021b4a2a.alma.1 | ALSA-2026:6907 |
| AlmaLinux:9 | nginx-mod-devel | 2:1.26.3-2.module_el9.7.0+223+9cd7031b.1 | ALSA-2026:7343 |
| AlmaLinux:9 | nginx-mod-devel | 2:1.20.1-24.el9_7.2.alma.1 | ALSA-2026:7002 |
| AlmaLinux:9 | nginx-mod-devel | 1:1.24.0-5.module_el9.7.0+220+47ec8b91.2.alma.1 | ALSA-2026:6923 |
| AlmaLinux:8 | nginx-mod-http-image-filter | 1:1.24.0-3.module_el8.10.0+4159+021b4a2a.alma.1 | ALSA-2026:6907 |
| AlmaLinux:9 | nginx-mod-http-image-filter | 1:1.24.0-5.module_el9.7.0+220+47ec8b91.2.alma.1 | ALSA-2026:6923 |
| AlmaLinux:9 | nginx-mod-http-image-filter | 2:1.26.3-2.module_el9.7.0+223+9cd7031b.1 | ALSA-2026:7343 |
| AlmaLinux:9 | nginx-mod-http-image-filter | 2:1.20.1-24.el9_7.2.alma.1 | ALSA-2026:7002 |
| AlmaLinux:8 | nginx-mod-http-perl | 1:1.24.0-3.module_el8.10.0+4159+021b4a2a.alma.1 | ALSA-2026:6907 |
| AlmaLinux:9 | nginx-mod-http-perl | 2:1.26.3-2.module_el9.7.0+223+9cd7031b.1 | ALSA-2026:7343 |
| AlmaLinux:9 | nginx-mod-http-perl | 1:1.24.0-5.module_el9.7.0+220+47ec8b91.2.alma.1 | ALSA-2026:6923 |
| AlmaLinux:9 | nginx-mod-http-perl | 2:1.20.1-24.el9_7.2.alma.1 | ALSA-2026:7002 |
| AlmaLinux:8 | nginx-mod-http-xslt-filter | 1:1.24.0-3.module_el8.10.0+4159+021b4a2a.alma.1 | ALSA-2026:6907 |
| AlmaLinux:9 | nginx-mod-http-xslt-filter | 2:1.26.3-2.module_el9.7.0+223+9cd7031b.1 | ALSA-2026:7343 |
| AlmaLinux:9 | nginx-mod-http-xslt-filter | 1:1.24.0-5.module_el9.7.0+220+47ec8b91.2.alma.1 | ALSA-2026:6923 |
| AlmaLinux:9 | nginx-mod-http-xslt-filter | 2:1.20.1-24.el9_7.2.alma.1 | ALSA-2026:7002 |
| AlmaLinux:8 | nginx-mod-mail | 1:1.24.0-3.module_el8.10.0+4159+021b4a2a.alma.1 | ALSA-2026:6907 |
| AlmaLinux:9 | nginx-mod-mail | 2:1.26.3-2.module_el9.7.0+223+9cd7031b.1 | ALSA-2026:7343 |
| AlmaLinux:9 | nginx-mod-mail | 2:1.20.1-24.el9_7.2.alma.1 | ALSA-2026:7002 |
| AlmaLinux:9 | nginx-mod-mail | 1:1.24.0-5.module_el9.7.0+220+47ec8b91.2.alma.1 | ALSA-2026:6923 |
| AlmaLinux:8 | nginx-mod-stream | 1:1.24.0-3.module_el8.10.0+4159+021b4a2a.alma.1 | ALSA-2026:6907 |
| AlmaLinux:9 | nginx-mod-stream | 2:1.20.1-24.el9_7.2.alma.1 | ALSA-2026:7002 |
| AlmaLinux:9 | nginx-mod-stream | 1:1.24.0-5.module_el9.7.0+220+47ec8b91.2.alma.1 | ALSA-2026:6923 |
| AlmaLinux:9 | nginx-mod-stream | 2:1.26.3-2.module_el9.7.0+223+9cd7031b.1 | ALSA-2026:7343 |
| Alpine:v3.22 | nginx | 1.28.3-r0 | ALPINE-CVE-2026-27651 |
| Alpine:v3.23 | nginx | 1.28.3-r0 | ALPINE-CVE-2026-27651 |
| Alpine:v3.24 | nginx | 1.28.3-r0 | ALPINE-CVE-2026-27651 |
| Debian:12 | nginx | 1.22.1-9+deb12u5 | DEBIAN-CVE-2026-27651 |
| Debian:13 | nginx | 1.26.3-3+deb13u3 | DEBIAN-CVE-2026-27651 |
| Debian:14 | nginx | 1.28.3-1 | DEBIAN-CVE-2026-27651 |
| Rocky Linux:10 | nginx | 2:1.26.3-2.el10_1.1 | RLSA-2026:6906 |
| Rocky Linux:8 | nginx | 1:1.24.0-3.module+el8.10.0+40144+38158758 | RLSA-2026:6907 |
| Rocky Linux:9 | nginx | 2:1.20.1-24.el9_7.2.rocky.0.1 | RLSA-2026:7002 |
| Rocky Linux:9 | nginx | 1:1.24.0-5.module+el9.7.0+40088+99dbd8cd.1.rocky.0.1 | RLSA-2026:6923 |
| Rocky Linux:9 | nginx | 2:1.26.3-2.module+el9.7.0+40103+2443f6d1 | RLSA-2026:7343 |
| Ubuntu:22.04:LTS | nginx | 1.18.0-6ubuntu14.10 | UBUNTU-CVE-2026-27651 |
| Ubuntu:24.04:LTS | nginx | 1.24.0-2ubuntu7.7 | UBUNTU-CVE-2026-27651 |
| Ubuntu:25.10 | nginx | 1.28.0-6ubuntu1.2 | UBUNTU-CVE-2026-27651 |
Affected products (as reported)
| Vendor | Product | Versions |
|---|---|---|
| F5 | NGINX Open Source | 1.29.0 – before 1.29.70.5.15 – before 1.28.3 |
| F5 | NGINX Plus | R36 – before R36 P3R35 – before R35 P2R34 – before *R33 – before *R32 – before R32 P5 |
Weakness: CWE-476 · Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
References
- https://my.f5.com/manage/s/article/K000160383 vendor-advisory
- https://access.redhat.com/security/cve/CVE-2026-27651 vdb-entry, x_refsource_REDHAT
- RHBZ#2450791 issue-tracking, x_refsource_REDHAT
- https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-27651.json x_sadp-csaf-vex
- https://access.redhat.com/errata/RHSA-2026:13634 vendor-advisory, x_refsource_REDHAT
- https://access.redhat.com/errata/RHSA-2026:6906 vendor-advisory, x_refsource_REDHAT
- https://access.redhat.com/errata/RHSA-2026:6907 vendor-advisory, x_refsource_REDHAT
- https://access.redhat.com/errata/RHSA-2026:15942 vendor-advisory, x_refsource_REDHAT
- https://access.redhat.com/errata/RHSA-2026:14836 vendor-advisory, x_refsource_REDHAT
- https://access.redhat.com/errata/RHSA-2026:13839 vendor-advisory, x_refsource_REDHAT
- https://access.redhat.com/errata/RHSA-2026:15943 vendor-advisory, x_refsource_REDHAT
- https://access.redhat.com/errata/RHSA-2026:15945 vendor-advisory, x_refsource_REDHAT
- https://access.redhat.com/errata/RHSA-2026:13680 vendor-advisory, x_refsource_REDHAT
- https://access.redhat.com/errata/RHSA-2026:15966 vendor-advisory, x_refsource_REDHAT
- https://access.redhat.com/errata/RHSA-2026:6923 vendor-advisory, x_refsource_REDHAT
- https://access.redhat.com/errata/RHSA-2026:7002 vendor-advisory, x_refsource_REDHAT
- https://access.redhat.com/errata/RHSA-2026:7343 vendor-advisory, x_refsource_REDHAT
- https://access.redhat.com/errata/RHSA-2026:8346 vendor-advisory, x_refsource_REDHAT
- https://access.redhat.com/errata/RHSA-2026:10065 vendor-advisory, x_refsource_REDHAT