diff --git a/locksordering.txt b/locksordering.txt
index 4a2c9e71721..7d750ac4a58 100644
--- a/locksordering.txt
+++ b/locksordering.txt
@@ -28,5 +28,9 @@ clearObserverState so that they cannot interleave which would leave Raft nodes i
 inconsistent observer states.
 
     jscmMu -> Account -> jsAccount
-    jscmMu -> stream.clsMu 
-    jscmMu -> RaftNode
\ No newline at end of file
+    jscmMu -> stream.clsMu
+    jscmMu -> RaftNode
+
+The "clsMu" lock protects the consumer list on a stream, used for signalling consumer activity.
+
+    stream -> clsMu
diff --git a/server/stream.go b/server/stream.go
index 8e8029e4ace..d8f3f6e4f0e 100644
--- a/server/stream.go
+++ b/server/stream.go
@@ -25,6 +25,7 @@ import (
 	"os"
 	"path/filepath"
 	"reflect"
+	"slices"
 	"strconv"
 	"strings"
 	"sync"
@@ -2267,8 +2268,12 @@ func (mset *stream) purge(preq *JSApiStreamPurgeRequest) (purged uint64, err err
 		fseq = ss.First
 	}
 
+	// Take a copy of cList to avoid o.purge() potentially taking the stream lock and
+	// violating the lock ordering.
 	mset.clsMu.RLock()
-	for _, o := range mset.cList {
+	cList := slices.Clone(mset.cList)
+	mset.clsMu.RUnlock()
+	for _, o := range cList {
 		start := fseq
 		o.mu.RLock()
 		// we update consumer sequences if:
@@ -2290,7 +2295,6 @@ func (mset *stream) purge(preq *JSApiStreamPurgeRequest) (purged uint64, err err
 			o.purge(start, lseq, isWider)
 		}
 	}
-	mset.clsMu.RUnlock()
 
 	return purged, nil
 }