NGINX ngx_mail_auth_http_module vulnerability

MITRE NVD CVE.ORG Print: PDF PDF

Summary

CVECVE-2026-27651
StatePUBLISHED
Assignerf5
Source PriorityCVE Program / NVD first with legacy fallback
Published2026-03-24 15:16:32 UTC
Updated2026-03-30 14:02:05 UTC
DescriptionWhen 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.

Risk And Classification

Primary CVSS: v4.0 8.7 HIGH from [email protected]

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

Problem Types: CWE-476 | CWE-476 CWE-476 NULL Pointer Dereference

VersionSourceTypeScoreSeverityVector
4.0[email protected]Secondary8.7HIGHCVSS: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/C...
4.0CNACVSS8.7HIGHCVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N
3.1[email protected]Primary7.5HIGHCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
3.1CNACVSS7.5HIGHCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

CVSS v4.0 Breakdown

Attack Vector
Network
Attack Complexity
Low
Attack Requirements
None
Privileges Required
None
User Interaction
None
Confidentiality
None
Integrity
None
Availability
High
Sub Conf.
None
Sub Integrity
None
Sub Availability
None

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

CVSS v3.1 Breakdown

Attack Vector
Network
Attack Complexity
Low
Privileges Required
None
User Interaction
None
Scope
Unchanged
Confidentiality
None
Integrity
None
Availability
High

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

NVD Known Affected Configurations (CPE 2.3)

TypeVendorProductVersionUpdateEditionLanguage
Application F5 Nginx Open Source All All All All
Application F5 Nginx Open Source All All All All

Vendor Declared Affected Products

SourceVendorProductVersionPlatforms
CNA F5 NGINX Open Source affected 1.29.0 1.29.7 semver Not specified
CNA F5 NGINX Open Source affected 0.5.15 1.28.3 semver Not specified
CNA F5 NGINX Plus affected R36 R36 P3 custom Not specified
CNA F5 NGINX Plus affected R35 R35 P2 custom Not specified
CNA F5 NGINX Plus affected R34 * custom Not specified
CNA F5 NGINX Plus affected R33 * custom Not specified
CNA F5 NGINX Plus affected R32 R32 P5 custom Not specified

References

ReferenceSourceLinkTags
my.f5.com/manage/s/article/K000160383 [email protected] my.f5.com Vendor Advisory
CVE Program record CVE.ORG www.cve.org canonical
NVD vulnerability detail NVD nvd.nist.gov canonical, analysis

Vendor Comments And Credit

Discovery Credit

CNA: F5 acknowledges Arkadi Vainbrand for bringing this issue to our attention and following the highest standards of coordinated disclosure. (en)

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