nginx: fix CVE-2026-27651

As per the advisory[1] mentioned in NVD[2], version 1.28.3 contains the fix.
Backport the commit[3] from 1.28.3 changelog matching the description.

[1] https://my.f5.com/manage/s/article/K000160383
[2] https://nvd.nist.gov/vuln/detail/CVE-2026-27651
[3] 0f71dd8ea9

Signed-off-by: Ankur Tyagi <ankur.tyagi85@gmail.com>
Signed-off-by: Anuj Mittal <anuj.mittal@oss.qualcomm.com>

meta-webserver/recipes-httpd/nginx/nginx-1.24.0/CVE-2026-27651.patch

@@ -0,0 +1,34 @@
+From 4f32484e99671d107d0d6c27c0c674f528d8c9ca Mon Sep 17 00:00:00 2001
+From: Sergey Kandaurov <pluknet@nginx.com>
+Date: Wed, 18 Mar 2026 16:39:37 +0400
+Subject: [PATCH] Mail: fixed clearing s->passwd in auth http requests.
+
+Previously, it was not properly cleared retaining length as part of
+authenticating with CRAM-MD5 and APOP methods that expect to receive
+password in auth response.  This resulted in null pointer dereference
+and worker process crash in subsequent auth attempts with CRAM-MD5.
+
+Reported by Arkadi Vainbrand.
+
+(cherry picked from commit 0f71dd8ea94ab8c123413b2e465be12a35392e9c)
+
+CVE: CVE-2026-27651
+Upstream-Status: Backport [https://github.com/nginx/nginx/commit/0f71dd8ea94ab8c123413b2e465be12a35392e9c]
+Signed-off-by: Ankur Tyagi <ankur.tyagi85@gmail.com>
+---
+ src/mail/ngx_mail_auth_http_module.c | 2 +-
+ 1 file changed, 1 insertion(+), 1 deletion(-)
+
+diff --git a/src/mail/ngx_mail_auth_http_module.c b/src/mail/ngx_mail_auth_http_module.c
+index 27f64b92e..d931183ae 100644
+--- a/src/mail/ngx_mail_auth_http_module.c
++++ b/src/mail/ngx_mail_auth_http_module.c
+@@ -1325,7 +1325,7 @@ ngx_mail_auth_http_create_request(ngx_mail_session_t *s, ngx_pool_t *pool,
+         b->last = ngx_cpymem(b->last, "Auth-Salt: ", sizeof("Auth-Salt: ") - 1);
+         b->last = ngx_copy(b->last, s->salt.data, s->salt.len);
+ 
+-        s->passwd.data = NULL;
++        ngx_str_null(&s->passwd);
+     }
+ 
+     b->last = ngx_cpymem(b->last, "Auth-Protocol: ",

meta-webserver/recipes-httpd/nginx/nginx_1.24.0.bb

@@ -5,6 +5,7 @@ LIC_FILES_CHKSUM = "file://LICENSE;md5=175abb631c799f54573dc481454c8632"
 SRC_URI:append = " \
                   file://CVE-2023-44487.patch \
                   file://CVE-2026-28755.patch \
+                  file://CVE-2026-27651.patch \
 "
 
 SRC_URI[sha256sum] = "77a2541637b92a621e3ee76776c8b7b40cf6d707e69ba53a940283e30ff2f55d"