CVE-2026-27651

Name	CVE-2026-27651
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.
Source	CVE (at NVD; CERT, ENISA, LWN, oss-sec, fulldisc, Debian ELTS, Red Hat, Ubuntu, Gentoo, SUSE bugzilla/CVE, GitHub advisories/code/issues, web search, more)

Vulnerable and fixed packages

The table below lists information on source packages.

Source Package	Release	Version	Status
nginx (PTS)	bullseye	1.18.0-6.1+deb11u3	vulnerable
	bullseye (security)	1.18.0-6.1+deb11u5	vulnerable
	bookworm	1.22.1-9+deb12u3	vulnerable
	bookworm (security)	1.22.1-9+deb12u4	vulnerable
	trixie (security), trixie	1.26.3-3+deb13u2	vulnerable
	forky, sid	1.28.3-2	fixed

The information below is based on the following data on fixed versions.

Package	Type	Release	Fixed Version	Urgency	Origin	Debian Bugs
nginx	source	(unstable)	1.28.3-1

Notes

[trixie] - nginx <no-dsa> (Minor issue)
[bookworm] - nginx <no-dsa> (Minor issue)
https://my.f5.com/manage/s/article/K000160383
Fixed by: https://github.com/nginx/nginx/commit/0f71dd8ea94ab8c123413b2e465be12a35392e9c (release-1.28.3)