diff --git a/app/vmselect/promql/exec_test.go b/app/vmselect/promql/exec_test.go
index 2c7c2e4058..b7efad70cd 100644
--- a/app/vmselect/promql/exec_test.go
+++ b/app/vmselect/promql/exec_test.go
@@ -2299,6 +2299,45 @@ func TestExecSuccess(t *testing.T) {
 		resultExpected := []netstorage.Result{r}
 		f(q, resultExpected)
 	})
+	t.Run(`histogram_quantile(single-value-valid-le-max-phi)`, func(t *testing.T) {
+		t.Parallel()
+		q := `histogram_quantile(1, (
+			label_set(100, "le", "200"),
+			label_set(0, "le", "55"),
+		))`
+		r := netstorage.Result{
+			MetricName: metricNameExpected,
+			Values:     []float64{200, 200, 200, 200, 200, 200},
+			Timestamps: timestampsExpected,
+		}
+		resultExpected := []netstorage.Result{r}
+		f(q, resultExpected)
+	})
+	t.Run(`histogram_quantile(single-value-valid-le-min-phi)`, func(t *testing.T) {
+		t.Parallel()
+		q := `histogram_quantile(0, (
+			label_set(100, "le", "200"),
+			label_set(0, "le", "55"),
+		))`
+		r := netstorage.Result{
+			MetricName: metricNameExpected,
+			Values:     []float64{55, 55, 55, 55, 55, 55},
+			Timestamps: timestampsExpected,
+		}
+		resultExpected := []netstorage.Result{r}
+		f(q, resultExpected)
+	})
+	t.Run(`histogram_quantile(single-value-valid-le-min-phi-no-zero-bucket)`, func(t *testing.T) {
+		t.Parallel()
+		q := `histogram_quantile(0, label_set(100, "le", "200"))`
+		r := netstorage.Result{
+			MetricName: metricNameExpected,
+			Values:     []float64{0, 0, 0, 0, 0, 0},
+			Timestamps: timestampsExpected,
+		}
+		resultExpected := []netstorage.Result{r}
+		f(q, resultExpected)
+	})
 	t.Run(`histogram_quantile(scalar-phi)`, func(t *testing.T) {
 		t.Parallel()
 		q := `histogram_quantile(time() / 2 / 1e3, label_set(100, "le", "200"))`
diff --git a/app/vmselect/promql/transform.go b/app/vmselect/promql/transform.go
index 445462846f..03a55a9e4a 100644
--- a/app/vmselect/promql/transform.go
+++ b/app/vmselect/promql/transform.go
@@ -447,7 +447,15 @@ func transformHistogramQuantile(tfa *transformFuncArg) ([]*timeseries, error) {
 				vPrev = v
 			}
 		}
-		if len(xss) == 0 {
+		vLast := nan
+		for len(xss) > 0 {
+			vLast = xss[len(xss)-1].ts.Values[i]
+			if !math.IsNaN(vLast) {
+				break
+			}
+			xss = xss[:len(xss)-1]
+		}
+		if vLast == 0 || math.IsNaN(vLast) {
 			return nan
 		}
 		if phi < 0 {
@@ -456,10 +464,6 @@ func transformHistogramQuantile(tfa *transformFuncArg) ([]*timeseries, error) {
 		if phi > 1 {
 			return inf
 		}
-		vLast := xss[len(xss)-1].ts.Values[i]
-		if vLast == 0 {
-			return nan
-		}
 		vReq := vLast * phi
 		vPrev = 0
 		lePrev := float64(0)
@@ -471,6 +475,11 @@ func transformHistogramQuantile(tfa *transformFuncArg) ([]*timeseries, error) {
 				continue
 			}
 			le := xs.le
+			if v <= 0 {
+				// Skip zero buckets.
+				lePrev = le
+				continue
+			}
 			if v < vReq {
 				vPrev = v
 				lePrev = le