diff --git a/docs/release-notes.d/slices-contains.change.md b/docs/release-notes.d/slices-contains.change.md
new file mode 100644
index 000000000..879aa19ae
--- /dev/null
+++ b/docs/release-notes.d/slices-contains.change.md
@@ -0,0 +1 @@
+Replace manual slice membership checks with `slices.Contains`
diff --git a/internal/exec/stages/disks/luks.go b/internal/exec/stages/disks/luks.go
index 72fde098b..037f5da8b 100644
--- a/internal/exec/stages/disks/luks.go
+++ b/internal/exec/stages/disks/luks.go
@@ -26,6 +26,7 @@ import (
 	"path"
 	"path/filepath"
 	"regexp"
+	"slices"
 	"strconv"
 	"strings"
 
@@ -572,12 +573,7 @@ func newLuksDump(devAlias string) (LuksDump, error) {
 }
 
 func (d LuksDump) hasFlag(flag string) bool {
-	for _, v := range d.Config.Flags {
-		if v == flag {
-			return true
-		}
-	}
-	return false
+	return slices.Contains(d.Config.Flags, flag)
 }
 
 // collect the cex card domains xx.xxxx
diff --git a/internal/resource/http.go b/internal/resource/http.go
index da1541fd0..231ddc521 100644
--- a/internal/resource/http.go
+++ b/internal/resource/http.go
@@ -26,6 +26,7 @@ import (
 	"net/http"
 	"net/url"
 	"os"
+	"slices"
 	"strings"
 	"time"
 
@@ -306,13 +307,7 @@ func shouldRetryHttp(statusCode int, opts FetchOptions) bool {
 		return true
 	}
 
-	for _, retryCode := range opts.RetryCodes {
-		if statusCode == retryCode {
-			return true
-		}
-	}
-
-	return false
+	return slices.Contains(opts.RetryCodes, statusCode)
 }
 
 // httpReaderWithHeader performs an HTTP request on the provided URL with the
diff --git a/internal/resource/http_test.go b/internal/resource/http_test.go
new file mode 100644
index 000000000..e301ca1fb
--- /dev/null
+++ b/internal/resource/http_test.go
@@ -0,0 +1,44 @@
+// Copyright 2026 Red Hat, Inc.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package resource
+
+import "testing"
+
+func TestShouldRetryHttp(t *testing.T) {
+	tests := []struct {
+		name       string
+		statusCode int
+		retryCodes []int
+		out        bool
+	}{
+		{"nil", 429, nil, false},
+		{"empty", 429, []int{}, false},
+		{"one", 429, []int{429}, true},
+		{"first", 408, []int{408, 429}, true},
+		{"last", 429, []int{408, 429}, true},
+		{"missing", 404, []int{408, 429}, false},
+		{"below server error", 499, nil, false},
+		{"server error", 500, nil, true},
+		{"higher server error", 503, []int{}, true},
+	}
+	for _, test := range tests {
+		t.Run(test.name, func(t *testing.T) {
+			opts := FetchOptions{RetryCodes: test.retryCodes}
+			if got := shouldRetryHttp(test.statusCode, opts); got != test.out {
+				t.Errorf("shouldRetryHttp(%d, %+v) = %t, want %t", test.statusCode, opts, got, test.out)
+			}
+		})
+	}
+}
diff --git a/internal/util/str.go b/internal/util/str.go
index dceae5efe..cf283866e 100644
--- a/internal/util/str.go
+++ b/internal/util/str.go
@@ -14,11 +14,8 @@
 
 package util
 
+import "slices"
+
 func StrSliceContains(slice []string, s string) bool {
-	for _, e := range slice {
-		if e == s {
-			return true
-		}
-	}
-	return false
+	return slices.Contains(slice, s)
 }