diff --git a/pkg/kv/kvserver/rangefeed/buffered_sender.go b/pkg/kv/kvserver/rangefeed/buffered_sender.go
index edf3494da24..7965ff7b945 100644
--- a/pkg/kv/kvserver/rangefeed/buffered_sender.go
+++ b/pkg/kv/kvserver/rangefeed/buffered_sender.go
@@ -7,10 +7,12 @@ package rangefeed
 
 import (
 	"context"
+	"math"
 	"sync"
 	"time"
 
 	"github.com/cockroachdb/cockroach/pkg/kv/kvpb"
+	"github.com/cockroachdb/cockroach/pkg/util/envutil"
 	"github.com/cockroachdb/cockroach/pkg/util/log"
 	"github.com/cockroachdb/cockroach/pkg/util/retry"
 	"github.com/cockroachdb/cockroach/pkg/util/stop"
@@ -18,6 +20,9 @@ import (
 	"github.com/cockroachdb/errors"
 )
 
+var bufferedSenderCapacity = envutil.EnvOrDefaultInt64(
+	"COCKROACH_BUFFERED_STREAM_CAPACITY_PER_STREAM", math.MaxInt64)
+
 //	┌─────────────────────────────────────────┐                                      MuxRangefeedEvent
 //	│            Node.MuxRangeFeed            │◄──────────────────────────────────────────────────┐
 //	└─────────────────┬───▲───────────────────┘                  ▲                                │
@@ -82,8 +87,10 @@ type BufferedSender struct {
 
 	queueMu struct {
 		syncutil.Mutex
-		stopped bool
-		buffer  *eventQueue
+		stopped  bool
+		capacity int64
+		buffer   *eventQueue
+		overflow bool
 	}
 
 	// Unblocking channel to notify the BufferedSender.run goroutine that there
@@ -98,6 +105,7 @@ func NewBufferedSender(
 		metrics: metrics,
 	}
 	bs.queueMu.buffer = newEventQueue()
+	bs.queueMu.capacity = bufferedSenderCapacity
 	bs.notifyDataC = make(chan struct{}, 1)
 	return bs
 }
@@ -117,6 +125,14 @@ func (bs *BufferedSender) SendBuffered(
 		log.Errorf(context.Background(), "stream sender is stopped")
 		return errors.New("stream sender is stopped")
 	}
+	if bs.queueMu.overflow {
+		log.Error(context.Background(), "buffer capacity exceeded")
+		return newRetryErrBufferCapacityExceeded()
+	}
+	if bs.queueMu.buffer.Len() >= bs.queueMu.capacity {
+		bs.queueMu.overflow = true
+		return newRetryErrBufferCapacityExceeded()
+	}
 	alloc.Use(context.Background())
 	bs.queueMu.buffer.pushBack(sharedMuxEvent{ev, alloc})
 	select {
@@ -224,7 +240,7 @@ func (bs *BufferedSender) run(ctx context.Context, stopper *stop.Stopper) error
 			return nil
 		case <-bs.notifyDataC:
 			for {
-				e, success := bs.popFront()
+				e, success, overflowed, remains := bs.popFront()
 				if success {
 					err := bs.sender.Send(e.ev)
 					e.alloc.Release(ctx)
@@ -241,6 +257,9 @@ func (bs *BufferedSender) run(ctx context.Context, stopper *stop.Stopper) error
 					if err != nil {
 						return err
 					}
+					if overflowed && remains == int64(0) {
+						return newRetryErrBufferCapacityExceeded()
+					}
 				} else {
 					break
 				}
@@ -249,11 +268,16 @@ func (bs *BufferedSender) run(ctx context.Context, stopper *stop.Stopper) error
 	}
 }
 
-func (bs *BufferedSender) popFront() (e sharedMuxEvent, success bool) {
+func (bs *BufferedSender) popFront() (
+	e sharedMuxEvent,
+	success bool,
+	overflowed bool,
+	remains int64,
+) {
 	bs.queueMu.Lock()
 	defer bs.queueMu.Unlock()
 	event, ok := bs.queueMu.buffer.popFront()
-	return event, ok
+	return event, ok, bs.queueMu.overflow, bs.queueMu.buffer.Len()
 }
 
 func (bs *BufferedSender) Start(ctx context.Context, stopper *stop.Stopper) error {
diff --git a/pkg/server/node.go b/pkg/server/node.go
index 634699c835d..efd5f347e72 100644
--- a/pkg/server/node.go
+++ b/pkg/server/node.go
@@ -2076,7 +2076,7 @@ func (n *Node) MuxRangeFeed(muxStream kvpb.Internal_MuxRangeFeedServer) error {
 	var sm streamManager
 	if kvserver.RangefeedUseBufferedSender.Get(&n.storeCfg.Settings.SV) {
 		sm = rangefeed.NewBufferedSender(lockedMuxStream, n.metrics)
-		log.Fatalf(ctx, "unimplemented: buffered sender for rangefeed #126560")
+		log.Infof(ctx, "using buffered sender for rangefeed")
 	} else {
 		sm = rangefeed.NewUnbufferedSender(lockedMuxStream, n.metrics)
 	}