High 7.5Published Mar 24, 2026

CVE-2026-27651NGINX ngx_mail_auth_http_module vulnerability

Updated under an hour ago (Oct 30, 2026, 4:40 AM ET)

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It affects F5 NGINX Open Source and 7 other products. Add what you run to find out whether that includes you.

No exploitation reported and no EPSS estimate yet.

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Start free and add your stackFree account, 3 products Every CVE for F5 NGINX Open Source Exploited in the last 30 days

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.

CVSS: 7.5 HIGH (v3.1, CNA)CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
Weakness (CWE): CWE-476
Known exploited: Not in CISA's KEV catalog
EPSS (exploitation in the next 30 days): Not loaded for this CVE
Assigned by: f5
NVD analysis: Modified
Record last updated: Jul 14, 2026
First seen by InfoSec Signals: Oct 9, 2026

Affected products

Affected products

F5 NGINX Open Source f5:nginx_open_source (from the name)	from 1.29.0 before 1.29.7; from 0.5.15 before 1.28.3	CNA record
F5 NGINX Plus f5:nginx_plus (from the name)	from R36 before R36 P3; from R35 before R35 P2; from R34; from R33; from R32 before R32 P5	CNA record
Red Hat Red Hat Enterprise Linux 10 redhat:enterprise_linux	from 2:1.26.3-2.el10_1.1 not affected	CISA ADP
Red Hat Red Hat Enterprise Linux 10.0 Extended Update Support redhat:enterprise_linux_eus	from 2:1.26.3-1.el10_0.8 not affected	CISA ADP
Red Hat Red Hat Enterprise Linux 9.0 Update Services for SAP Solutions redhat:rhel_e4s	from 1:1.20.1-10.el9_0.3 not affected	CISA ADP
Red Hat Red Hat Enterprise Linux 9.4 Extended Update Support redhat:rhel_eus	from 1:1.20.1-16.el9_4.5 not affected	CISA ADP
Red Hat Red Hat Hardened Images redhat:hummingbird	from 1.30.0-1.hum1 not affected	CISA ADP
Red Hat Red Hat Update Infrastructure 5 redhat:rhui	from 1776868774 not affected	CISA ADP
f5 nginx_open_source f5:nginx_open_source	from 0.5.15 through 0.9.7; from 1.0.0 before 1.28.3; from 1.29.0 before 1.29.7	NVD
f5 nginx_plus f5:nginx_plus	from r33 before r35; r32; r32; r32; r32; r32; r35; r35; and 3 more ranges	NVD

References

References

https://my.f5.com/manage/s/article/K000160383	vendor-advisory
https://access.redhat.com/errata/RHSA-2026:10065
https://access.redhat.com/errata/RHSA-2026:13634
https://access.redhat.com/errata/RHSA-2026:13680
https://access.redhat.com/errata/RHSA-2026:13839
https://access.redhat.com/errata/RHSA-2026:14836
https://access.redhat.com/errata/RHSA-2026:15942
https://access.redhat.com/errata/RHSA-2026:15943
https://access.redhat.com/errata/RHSA-2026:15945
https://access.redhat.com/errata/RHSA-2026:15966
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The CVE record on cve.org NVD's entry

The CVE record is authoritative. Products marked “from the name” were identified from the CNA's free-text names, not a CPE, and are matched less certainly. This product uses the NVD API but is not endorsed or certified by the NVD.