CVE-2026-27651

NGINX ngx_mail_auth_http_module vulnerability

HIGH 8.7

At a glance

Source: NVD
EPSS: EPSS 0.95 % · percentile 61 (2026-10-28)
State: PUBLISHED
Published: 2026-03-24 14:13 UTC
Updated: 2026-07-15 01:13 UTC
Assigner: f5
NVD status: Modified

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.

Weaknesses (CWE)

CWE-476 — NULL Pointer Dereference

References

Scores

Version	Score	Vector	Scored by
CVSS 3.1	HIGH 7.5	CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H	f5
CVSS 4.0	HIGH 8.7	CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N	f5
CVSS 3.1	HIGH 7.5	CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H	redhat-SADP
CVSS 4.0	HIGH 8.7	CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/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	NVD · f5sirt@f5.com (Secondary)
CVSS 3.1	HIGH 7.5	CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H	NVD · f5sirt@f5.com (Secondary)
CVSS 3.1	HIGH 7.5	CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H	NVD · 0b0ca135-0b70-47e7-9f44-1890c2a1c46c (Secondary)

European references

ENISA EUVD · EUVD-2026-14880
GCVE · GCVE-0-2026-27651

CERT-FR advisories

CERTFR-2026-AVI-1056 — Multiples vulnérabilités dans les produits Splunk · cert.ssi.gouv.fr
CERTFR-2026-AVI-0376 — Multiples vulnérabilités dans les produits Microsoft · cert.ssi.gouv.fr
CERTFR-2026-AVI-0352 — Multiples vulnérabilités dans les produits F5 · cert.ssi.gouv.fr

Affected configurations (NVD CPE)

cpe:2.3:a:f5:nginx_open_source:*:*:*:*:*:*:*:* ≥ 0.5.15 ≤ 0.9.7
cpe:2.3:a:f5:nginx_open_source:*:*:*:*:*:*:*:* ≥ 1.0.0 < 1.28.3
cpe:2.3:a:f5:nginx_open_source:*:*:*:*:*:*:*:* ≥ 1.29.0 < 1.29.7
cpe:2.3:a:f5:nginx_plus:*:*:*:*:*:*:*:* ≥ r33 < r35
cpe:2.3:a:f5:nginx_plus:r32:-:*:*:*:*:*:*
cpe:2.3:a:f5:nginx_plus:r32:p1:*:*:*:*:*:*
cpe:2.3:a:f5:nginx_plus:r32:p2:*:*:*:*:*:*
cpe:2.3:a:f5:nginx_plus:r32:p3:*:*:*:*:*:*
cpe:2.3:a:f5:nginx_plus:r32:p4:*:*:*:*:*:*
cpe:2.3:a:f5:nginx_plus:r35:-:*:*:*:*:*:*
cpe:2.3:a:f5:nginx_plus:r35:p1:*:*:*:*:*:*
cpe:2.3:a:f5:nginx_plus:r36:-:*:*:*:*:*:*
cpe:2.3:a:f5:nginx_plus:r36:p1:*:*:*:*:*:*
cpe:2.3:a:f5:nginx_plus:r36:p2:*:*:*:*:*:*

Affected products

Product	Versions
F5 · NGINX Open Source	affected 1.29.0 < 1.29.7 ; affected 0.5.15 < 1.28.3
F5 · NGINX Plus	affected R36 < R36 P3 ; affected R35 < R35 P2 ; affected R34 < * ; affected R33 < * ; affected R32 < R32 P5

Sources

Source	Licence
CVE List (CVEProject cvelistV5)	CVE Program Terms of Use
EPSS (FIRST.org)	FIRST — attribution requested
ENISA EUVD	ENISA — reproduction authorised, source acknowledged
CERT-FR (ANSSI)	Licence Ouverte / Etalab 2.0
NVD (NIST) via fkie-cad/nvd-json-data-feeds	Public domain — this product uses data from the NVD API but is not endorsed or certified by the NVD