diff --git a/meta-networking/recipes-support/unbound/unbound/CVE-2026-42534.patch b/meta-networking/recipes-support/unbound/unbound/CVE-2026-42534.patch
new file mode 100644
index 0000000000..aed793ec5c
--- /dev/null
+++ b/meta-networking/recipes-support/unbound/unbound/CVE-2026-42534.patch
@@ -0,0 +1,70 @@
+From 0d649a36fd3c47f1b75ca90ce10e52cb4ae3d253 Mon Sep 17 00:00:00 2001
+From: "W.C.A. Wijngaards" <wouter@nlnetlabs.nl>
+Date: Wed, 20 May 2026 10:19:08 +0200
+Subject: [PATCH] - Fix CVE-2026-42534, Jostle logic bypass degrades resolution
+   performance. Thanks to Qifan Zhang, Palo Alto Networks, for the   report.
+
+(cherry picked from commit a794c87578c963606a6fb00a54c46fcf935f519a)
+
+CVE: CVE-2026-42534
+Upstream-Status: Backport [https://github.com/NLnetLabs/unbound/commit/a794c87578c963606a6fb00a54c46fcf935f519a]
+
+Dropped changes to the Changelog file.
+
+Signed-off-by: Ankur Tyagi <ankur.tyagi85@gmail.com>
+---
+ services/mesh.c | 14 ++++++++++----
+ services/mesh.h |  6 ++++++
+ 2 files changed, 16 insertions(+), 4 deletions(-)
+
+diff --git a/services/mesh.c b/services/mesh.c
+index 3212a6abf..23499dcef 100644
+--- a/services/mesh.c
++++ b/services/mesh.c
+@@ -296,12 +296,14 @@ int mesh_make_new_space(struct mesh_area* mesh, sldns_buffer* qbuf)
+ 	if(mesh->num_reply_states < mesh->max_reply_states)
+ 		return 1;
+ 	/* try to kick out a jostle-list item */
+-	if(m && m->reply_list && m->list_select == mesh_jostle_list) {
++	if(m && m->list_select == mesh_jostle_list) {
+ 		/* how old is it? */
+ 		struct timeval age;
+-		timeval_subtract(&age, mesh->env->now_tv,
+-			&m->reply_list->start_time);
+-		if(timeval_smaller(&mesh->jostle_max, &age)) {
++		if(m->has_first_reply_time)
++			timeval_subtract(&age, mesh->env->now_tv,
++				&m->first_reply_time);
++		if(!m->has_first_reply_time ||
++			timeval_smaller(&mesh->jostle_max, &age)) {
+ 			/* its a goner */
+ 			log_nametypeclass(VERB_ALGO, "query jostled out to "
+ 				"make space for a new one",
+@@ -1960,6 +1962,10 @@ int mesh_state_add_reply(struct mesh_state* s, struct edns_data* edns,
+ 	r->qid = qid;
+ 	r->qflags = qflags;
+ 	r->start_time = *s->s.env->now_tv;
++	if(s->reply_list == NULL && !s->has_first_reply_time) {
++		s->first_reply_time = r->start_time;
++		s->has_first_reply_time = 1;
++	}
+ 	r->next = s->reply_list;
+ 	r->qname = regional_alloc_init(s->s.region, qinfo->qname,
+ 		s->s.qinfo.qname_len);
+diff --git a/services/mesh.h b/services/mesh.h
+index f19f423a8..a61f90993 100644
+--- a/services/mesh.h
++++ b/services/mesh.h
+@@ -189,6 +189,12 @@ struct mesh_state {
+ 	struct module_qstate s;
+ 	/** the list of replies to clients for the results */
+ 	struct mesh_reply* reply_list;
++	/** if it has a first reply time */
++	int has_first_reply_time;
++	/** wall-clock time the first client reply was attached;
++	 *  used by mesh_make_new_space() so duplicate retransmits
++	 *  cannot reset jostle aging. */
++	struct timeval first_reply_time;
+ 	/** the list of callbacks for the results */
+ 	struct mesh_cb* cb_list;
+ 	/** set of superstates (that want this state's result) 
diff --git a/meta-networking/recipes-support/unbound/unbound_1.24.2.bb b/meta-networking/recipes-support/unbound/unbound_1.24.2.bb
index 0688b8a78b..a70ae4c9a3 100644
--- a/meta-networking/recipes-support/unbound/unbound_1.24.2.bb
+++ b/meta-networking/recipes-support/unbound/unbound_1.24.2.bb
@@ -18,6 +18,7 @@ SRC_URI = "git://github.com/NLnetLabs/unbound.git;protocol=https;branch=master;t
            file://CVE-2026-32792.patch \
            file://CVE-2026-40622.patch \
            file://CVE-2026-41292.patch \
+           file://CVE-2026-42534.patch \
            "
 
 SRCREV = "f6269baa605d31859f28770e01a24e3677e5f82c"