diff --git a/src/sonic-frr/patch/0066-lib-fix-srv6-locator-flags-propagated-to-isis.patch b/src/sonic-frr/patch/0066-lib-fix-srv6-locator-flags-propagated-to-isis.patch
new file mode 100644
index 000000000000..b872ff9cbf8c
--- /dev/null
+++ b/src/sonic-frr/patch/0066-lib-fix-srv6-locator-flags-propagated-to-isis.patch
@@ -0,0 +1,41 @@
+From 03d2ad01a4fd4aa6df4b1ec64249fb391405a61f Mon Sep 17 00:00:00 2001
+
+From: Philippe Guibert <philippe.guibert@6wind.com>
+
+Subject: [PATCH] lib: fix srv6 locator flags propagated to isis
+
+When usid is not used, the isis_srv6_topo1 test does not work.
+The SID prefix allocated by isis is different when the usid
+flags is set or not. When the flags is not transmitted to isis,
+the SID allocated is supposed to be a 128 bit mask length SID,
+which is not what the isis_srv6_topo1 test is supposed to obtain.
+
+Fix this by exchanging the flags locator value in the zclient api.
+
+Fixes: 9b7491e1fc04 ("lib: Add support for flags to the SRv6 locator")
+
+Signed-off-by: Philippe Guibert <philippe.guibert@6wind.com>
+---
+ lib/zclient.c |    2 ++
+ 1 file changed, 2 insertions(+)
+
+diff --git a/lib/zclient.c b/lib/zclient.c
+index 64515c754..269c3e9ba 100644
+--- a/lib/zclient.c
++++ b/lib/zclient.c
+@@ -1125,6 +1125,7 @@ int zapi_srv6_locator_encode(struct stream *s, const struct srv6_locator *l)
+ 	stream_put(s, l->name, strlen(l->name));
+ 	stream_putw(s, l->prefix.prefixlen);
+ 	stream_put(s, &l->prefix.prefix, sizeof(l->prefix.prefix));
++	stream_putc(s, l->flags);
+ 	return 0;
+ }
+ 
+@@ -1140,6 +1141,7 @@ int zapi_srv6_locator_decode(struct stream *s, struct srv6_locator *l)
+ 	STREAM_GETW(s, l->prefix.prefixlen);
+ 	STREAM_GET(&l->prefix.prefix, s, sizeof(l->prefix.prefix));
+ 	l->prefix.family = AF_INET6;
++	STREAM_GETC(s, l->flags);
+ 	return 0;
+ 
+ stream_failure:
diff --git a/src/sonic-frr/patch/series b/src/sonic-frr/patch/series
index fc7841bb71d1..7f68378272ec 100644
--- a/src/sonic-frr/patch/series
+++ b/src/sonic-frr/patch/series
@@ -45,3 +45,4 @@
 0063-Patch-to-send-tag-value-associated-with-route-via-ne.patch
 0064-SRv6-BGP-SID-reachability.patch
 0065-zebra-display-srv6-encapsulation-source-address-when-configured.patch
+0066-lib-fix-srv6-locator-flags-propagated-to-isis.patch