diff --git a/src/_pytest/junitxml.py b/src/_pytest/junitxml.py
index 492df77f3..502799aa1 100644
--- a/src/_pytest/junitxml.py
+++ b/src/_pytest/junitxml.py
@@ -61,7 +61,7 @@ def bin_xml_escape(arg: object) -> str:
     # Char ::= #x9 | #xA | #xD | [#x20-#xD7FF] | [#xE000-#xFFFD] | [#x10000-#x10FFFF]
     # For an unknown(?) reason, we disallow #x7F (DEL) as well.
     illegal_xml_re = (
-        "[^\u0009\u000a\u000d\u0020-\u007e\u0080-\ud7ff\ue000-\ufffd\u10000-\u10ffFF]"
+        "[^\u0009\u000a\u000d\u0020-\u007e\u0080-\ud7ff\ue000-\ufffd\u10000-\u10ffff]"
     )
     return re.sub(illegal_xml_re, repl, str(arg))