A flaw was found in GLib. A buffer over-read can occur in the gregexreplace function when used with the GREGEXRAW compile flag and case-change replacement escapes because the stringappend function processes matched substrings using UTF-8 functions that assume valid UTF-8 input, even when the string is treated as raw bytes. This vulnerability can cause a minor information disclosure of 1-5 bytes and a denial of service when the buffer over-read crosses a page boundary.