diff --git a/api/auth/center.go b/api/auth/center.go
index acbaad943..bc9107d05 100644
--- a/api/auth/center.go
+++ b/api/auth/center.go
@@ -37,8 +37,8 @@ type (
 	}
 
 	center struct {
-		reg     *regexpSubmatcher
-		postReg *regexpSubmatcher
+		reg     *RegexpSubmatcher
+		postReg *RegexpSubmatcher
 		cli     tokens.Credentials
 	}
 
@@ -88,13 +88,13 @@ var _ io.ReadSeeker = prs(0)
 func New(neoFS tokens.NeoFS, key *keys.PrivateKey, config *cache.Config) Center {
 	return &center{
 		cli:     tokens.New(neoFS, key, config),
-		reg:     &regexpSubmatcher{re: authorizationFieldRegexp},
-		postReg: &regexpSubmatcher{re: postPolicyCredentialRegexp},
+		reg:     NewRegexpMatcher(authorizationFieldRegexp),
+		postReg: NewRegexpMatcher(postPolicyCredentialRegexp),
 	}
 }
 
 func (c *center) parseAuthHeader(header string) (*authHeader, error) {
-	submatches := c.reg.getSubmatches(header)
+	submatches := c.reg.GetSubmatches(header)
 	if len(submatches) != authHeaderPartsNum {
 		return nil, apiErrors.GetAPIError(apiErrors.ErrAuthorizationHeaderMalformed)
 	}
@@ -203,7 +203,7 @@ func (c *center) checkFormData(r *http.Request) (*accessbox.Box, error) {
 		return nil, ErrNoAuthorizationHeader
 	}
 
-	submatches := c.postReg.getSubmatches(MultipartFormValue(r, "x-amz-credential"))
+	submatches := c.postReg.GetSubmatches(MultipartFormValue(r, "x-amz-credential"))
 	if len(submatches) != 4 {
 		return nil, apiErrors.GetAPIError(apiErrors.ErrAuthorizationHeaderMalformed)
 	}
@@ -277,7 +277,7 @@ func (c *center) checkSign(authHeader *authHeader, box *accessbox.Box, request *
 		if _, err := signer.Sign(request, nil, authHeader.Service, authHeader.Region, signatureDateTime); err != nil {
 			return fmt.Errorf("failed to sign temporary HTTP request: %w", err)
 		}
-		signature = c.reg.getSubmatches(request.Header.Get(AuthorizationHdr))["v4_signature"]
+		signature = c.reg.GetSubmatches(request.Header.Get(AuthorizationHdr))["v4_signature"]
 	}
 
 	if authHeader.SignatureV4 != signature {
diff --git a/api/auth/center_test.go b/api/auth/center_test.go
index 8318b5be4..8b7a8d8a8 100644
--- a/api/auth/center_test.go
+++ b/api/auth/center_test.go
@@ -13,7 +13,7 @@ func TestAuthHeaderParse(t *testing.T) {
 	defaultHeader := "AWS4-HMAC-SHA256 Credential=oid0cid/20210809/us-east-1/s3/aws4_request, SignedHeaders=host;x-amz-content-sha256;x-amz-date, Signature=2811ccb9e242f41426738fb1f"
 
 	center := &center{
-		reg: &regexpSubmatcher{re: authorizationFieldRegexp},
+		reg: NewRegexpMatcher(authorizationFieldRegexp),
 	}
 
 	for _, tc := range []struct {
diff --git a/api/auth/regexp_utils.go b/api/auth/regexp_utils.go
index 1e9b2ddeb..4b05e802a 100644
--- a/api/auth/regexp_utils.go
+++ b/api/auth/regexp_utils.go
@@ -2,11 +2,17 @@ package auth
 
 import "regexp"
 
-type regexpSubmatcher struct {
+type RegexpSubmatcher struct {
 	re *regexp.Regexp
 }
 
-func (r *regexpSubmatcher) getSubmatches(target string) map[string]string {
+// NewRegexpMatcher creates a new regexp sub matcher.
+func NewRegexpMatcher(re *regexp.Regexp) *RegexpSubmatcher {
+	return &RegexpSubmatcher{re: re}
+}
+
+// GetSubmatches returns matches from provided string. Zero length indicates no match.
+func (r *RegexpSubmatcher) GetSubmatches(target string) map[string]string {
 	matches := r.re.FindStringSubmatch(target)
 	l := len(matches)
 
diff --git a/api/handler/copy.go b/api/handler/copy.go
index 69ee9578e..50b11b8e6 100644
--- a/api/handler/copy.go
+++ b/api/handler/copy.go
@@ -3,10 +3,11 @@ package handler
 import (
 	"net/http"
 	"net/url"
-	"strings"
+	"regexp"
 	"time"
 
 	"github.com/nspcc-dev/neofs-s3-gw/api"
+	"github.com/nspcc-dev/neofs-s3-gw/api/auth"
 	"github.com/nspcc-dev/neofs-s3-gw/api/data"
 	"github.com/nspcc-dev/neofs-s3-gw/api/errors"
 	"github.com/nspcc-dev/neofs-s3-gw/api/layer"
@@ -25,14 +26,16 @@ const (
 	copyDirective    = "COPY"
 )
 
+var copySourceMatcher = auth.NewRegexpMatcher(regexp.MustCompile(`^/?(?P<bucket_name>[a-z0-9.\-]{3,63})/(?P<object_name>.+)$`))
+
 // path2BucketObject returns a bucket and an object.
-func path2BucketObject(path string) (bucket, prefix string) {
-	path = strings.TrimPrefix(path, api.SlashSeparator)
-	m := strings.Index(path, api.SlashSeparator)
-	if m < 0 {
-		return path, ""
+func path2BucketObject(path string) (string, string, error) {
+	matches := copySourceMatcher.GetSubmatches(path)
+	if len(matches) != 2 {
+		return "", "", errors.GetAPIError(errors.ErrInvalidRequest)
 	}
-	return path[:m], path[m+len(api.SlashSeparator):]
+
+	return matches["bucket_name"], matches["object_name"], nil
 }
 
 func (h *handler) CopyObjectHandler(w http.ResponseWriter, r *http.Request) {
@@ -59,7 +62,11 @@ func (h *handler) CopyObjectHandler(w http.ResponseWriter, r *http.Request) {
 		src = u.Path
 	}
 
-	srcBucket, srcObject := path2BucketObject(src)
+	srcBucket, srcObject, err := path2BucketObject(src)
+	if err != nil {
+		h.logAndSendError(w, "invalid source copy", reqInfo, err)
+		return
+	}
 
 	p := &layer.HeadObjectParams{
 		Object:    srcObject,
diff --git a/api/handler/copy_test.go b/api/handler/copy_test.go
index 2a13ab038..01b412a58 100644
--- a/api/handler/copy_test.go
+++ b/api/handler/copy_test.go
@@ -93,3 +93,75 @@ func getObjectTagging(t *testing.T, tc *handlerContext, bktName, objName, versio
 	require.NoError(t, err)
 	return tagging
 }
+
+func TestSourceCopyRegexp(t *testing.T) {
+	for _, tc := range []struct {
+		path    string
+		err     bool
+		bktName string
+		objName string
+	}{
+		{
+			path:    "/bucket/object",
+			err:     false,
+			bktName: "bucket",
+			objName: "object",
+		},
+		{
+			path:    "bucket/object",
+			err:     false,
+			bktName: "bucket",
+			objName: "object",
+		},
+		{
+			path:    "sub-bucket/object",
+			err:     false,
+			bktName: "sub-bucket",
+			objName: "object",
+		},
+		{
+			path:    "bucket.domain/object",
+			err:     false,
+			bktName: "bucket.domain",
+			objName: "object",
+		},
+		{
+			path:    "bucket/object/deep",
+			err:     false,
+			bktName: "bucket",
+			objName: "object/deep",
+		},
+		{
+			path: "bucket",
+			err:  true,
+		},
+		{
+			path: "/bucket",
+			err:  true,
+		},
+		{
+			path: "invalid+bucket/object",
+			err:  true,
+		},
+		{
+			path: "invaliDBucket/object",
+			err:  true,
+		},
+		{
+			path: "i/object",
+			err:  true,
+		},
+	} {
+		t.Run("", func(t *testing.T) {
+			bktName, objName, err := path2BucketObject(tc.path)
+			if tc.err {
+				require.Error(t, err)
+				return
+			}
+
+			require.NoError(t, err)
+			require.Equal(t, tc.bktName, bktName)
+			require.Equal(t, tc.objName, objName)
+		})
+	}
+}
diff --git a/api/handler/multipart_upload.go b/api/handler/multipart_upload.go
index 1dca5e45e..8e9d62f83 100644
--- a/api/handler/multipart_upload.go
+++ b/api/handler/multipart_upload.go
@@ -266,7 +266,11 @@ func (h *handler) UploadPartCopy(w http.ResponseWriter, r *http.Request) {
 		versionID = u.Query().Get(api.QueryVersionID)
 		src = u.Path
 	}
-	srcBucket, srcObject := path2BucketObject(src)
+	srcBucket, srcObject, err := path2BucketObject(src)
+	if err != nil {
+		h.logAndSendError(w, "invalid source copy", reqInfo, err)
+		return
+	}
 
 	srcRange, err := parseRange(r.Header.Get(api.AmzCopySourceRange))
 	if err != nil {
diff --git a/api/router.go b/api/router.go
index f6c5c10e0..d5b37520d 100644
--- a/api/router.go
+++ b/api/router.go
@@ -219,7 +219,7 @@ func Attach(r *mux.Router, domains []string, m MaxClients, h Handler, center aut
 		bucket.Methods(http.MethodHead).Path("/{object:.+}").HandlerFunc(
 			m.Handle(metrics.APIStats("headobject", h.HeadObjectHandler))).Name("HeadObject")
 		// CopyObjectPart
-		bucket.Methods(http.MethodPut).Path("/{object:.+}").HeadersRegexp(hdrAmzCopySource, ".*?(\\/|%2F).*?").HandlerFunc(m.Handle(metrics.APIStats("uploadpartcopy", h.UploadPartCopy))).Queries("partNumber", "{partNumber:[0-9]+}", "uploadId", "{uploadId:.*}").
+		bucket.Methods(http.MethodPut).Path("/{object:.+}").Headers(hdrAmzCopySource, "").HandlerFunc(m.Handle(metrics.APIStats("uploadpartcopy", h.UploadPartCopy))).Queries("partNumber", "{partNumber:[0-9]+}", "uploadId", "{uploadId:.*}").
 			Name("UploadPartCopy")
 		// PutObjectPart
 		bucket.Methods(http.MethodPut).Path("/{object:.+}").HandlerFunc(
@@ -286,7 +286,7 @@ func Attach(r *mux.Router, domains []string, m MaxClients, h Handler, center aut
 			m.Handle(metrics.APIStats("getobject", h.GetObjectHandler))).
 			Name("GetObject")
 		// CopyObject
-		bucket.Methods(http.MethodPut).Path("/{object:.+}").HeadersRegexp(hdrAmzCopySource, ".*?(\\/|%2F).*?").HandlerFunc(m.Handle(metrics.APIStats("copyobject", h.CopyObjectHandler))).
+		bucket.Methods(http.MethodPut).Path("/{object:.+}").Headers(hdrAmzCopySource, "").HandlerFunc(m.Handle(metrics.APIStats("copyobject", h.CopyObjectHandler))).
 			Name("CopyObject")
 		// PutObjectRetention
 		bucket.Methods(http.MethodPut).Path("/{object:.+}").HandlerFunc(