diff --git a/modules/objdetect/src/face_recognize.cpp b/modules/objdetect/src/face_recognize.cpp
index b024c787eb..639aa4b471 100644
--- a/modules/objdetect/src/face_recognize.cpp
+++ b/modules/objdetect/src/face_recognize.cpp
@@ -61,9 +61,10 @@ public:
     }
     double match(InputArray _face_feature1, InputArray _face_feature2, int dis_type) const override
     {
-        Mat face_feature1 = _face_feature1.getMat(), face_feature2 = _face_feature2.getMat();
-        normalize(face_feature1, face_feature1);
-        normalize(face_feature2, face_feature2);
+        // match() is const and takes InputArray: never write through to the caller's buffers.
+        Mat face_feature1, face_feature2;
+        normalize(_face_feature1, face_feature1);
+        normalize(_face_feature2, face_feature2);
 
         if(dis_type == DisType::FR_COSINE){
             return sum(face_feature1.mul(face_feature2))[0];
diff --git a/modules/objdetect/test/test_face.cpp b/modules/objdetect/test/test_face.cpp
index e55401c061..34b80bd334 100644
--- a/modules/objdetect/test/test_face.cpp
+++ b/modules/objdetect/test/test_face.cpp
@@ -213,4 +213,25 @@ TEST(Objdetect_face_recognition, regression)
     }
 }
 
+TEST(Objdetect_face_recognition, match_does_not_modify_input)
+{
+    std::string recog_model = findDataFile("dnn/onnx/models/face_recognizer_fast.onnx", false);
+    Ptr<FaceRecognizerSF> faceRecognizer = FaceRecognizerSF::create(recog_model, "");
+
+    // match() is declared const and takes both features as InputArray, so it must leave
+    // the caller's data untouched.
+    Mat feature1(1, 128, CV_32F), feature2(1, 128, CV_32F);
+    randu(feature1, Scalar::all(-10), Scalar::all(10));
+    randu(feature2, Scalar::all(-10), Scalar::all(10));
+    Mat expected1 = feature1.clone(), expected2 = feature2.clone();
+
+    faceRecognizer->match(feature1, feature2, FaceRecognizerSF::DisType::FR_COSINE);
+    EXPECT_EQ(0, cvtest::norm(expected1, feature1, NORM_INF)) << "FR_COSINE changed input 1";
+    EXPECT_EQ(0, cvtest::norm(expected2, feature2, NORM_INF)) << "FR_COSINE changed input 2";
+
+    faceRecognizer->match(feature1, feature2, FaceRecognizerSF::DisType::FR_NORM_L2);
+    EXPECT_EQ(0, cvtest::norm(expected1, feature1, NORM_INF)) << "FR_NORM_L2 changed input 1";
+    EXPECT_EQ(0, cvtest::norm(expected2, feature2, NORM_INF)) << "FR_NORM_L2 changed input 2";
+}
+
 }} // namespace