diff --git a/bind.go b/bind.go
index 149fe1d6..af8643ab 100644
--- a/bind.go
+++ b/bind.go
@@ -8,6 +8,7 @@ import (
 	"encoding/xml"
 	"errors"
 	"fmt"
+	"io"
 	"mime/multipart"
 	"net/http"
 	"reflect"
@@ -71,6 +72,22 @@ func (b *DefaultBinder) BindBody(c Context, i interface{}) (err error) {
 		return
 	}
 
+	// For unknown ContentLength (-1), check if body is actually empty
+	if req.ContentLength == -1 {
+		// Peek at the first byte to see if there's any content
+		var buf [1]byte
+		n, readErr := req.Body.Read(buf[:])
+		if readErr != nil && readErr != io.EOF {
+			return NewHTTPError(http.StatusBadRequest, readErr.Error()).SetInternal(readErr)
+		}
+		if n == 0 {
+			// Body is empty, return without error
+			return
+		}
+		// There's content, put the byte back by creating a new reader
+		req.Body = io.NopCloser(io.MultiReader(strings.NewReader(string(buf[:n])), req.Body))
+	}
+
 	// mediatype is found like `mime.ParseMediaType()` does it
 	base, _, _ := strings.Cut(req.Header.Get(HeaderContentType), ";")
 	mediatype := strings.TrimSpace(base)
diff --git a/bind_test.go b/bind_test.go
index 6aa0cce3..060845bd 100644
--- a/bind_test.go
+++ b/bind_test.go
@@ -1082,6 +1082,14 @@ func TestDefaultBinder_BindBody(t *testing.T) {
 			givenContent:     strings.NewReader(""),
 			expect:           &Node{ID: 0, Node: ""},
 		},
+		{
+			name:             "ok, POST with empty body and ContentLength -1 (Issue #2813)",
+			givenURL:         "/api/real_node/endpoint?node=xxx",
+			givenMethod:      http.MethodPost,
+			givenContent:     strings.NewReader(""),
+			whenChunkedBody:  true, // This sets ContentLength to -1
+			expect:           &Node{ID: 0, Node: ""},
+		},
 		{
 			name:             "ok, JSON POST bind to struct with: path + query + chunked body",
 			givenURL:         "/api/real_node/endpoint?node=xxx",