diff --git a/History.md b/History.md
index 8753a6d3..1c0d0755 100644
--- a/History.md
+++ b/History.md
@@ -1,3 +1,5 @@
+- 'Fix possible StringIndexOutOfBoundsException when extracting XMP.'
+
 2.23.1
 =======
 2026-05-13
diff --git a/validator/src/main/java/org/mustangproject/validator/PDFValidator.java b/validator/src/main/java/org/mustangproject/validator/PDFValidator.java
index 993a2d0a..f8fa6328 100644
--- a/validator/src/main/java/org/mustangproject/validator/PDFValidator.java
+++ b/validator/src/main/java/org/mustangproject/validator/PDFValidator.java
@@ -131,8 +131,10 @@ public class PDFValidator extends Validator {
 		String xmp;
 		if (zi.getXMP() == null) {
 			xmp = null;
-		} else {
+		} else if (zi.getXMP().indexOf('<') > 0) {
 			xmp = zi.getXMP().substring(zi.getXMP().indexOf('<'));
+		} else {
+			xmp = zi.getXMP();
 		}
 
 		final Document docXMP;