Affected: Ubuntu:16.04:LTS: libxml-parser-perl, Ubuntu:18.04:LTS: libxml-parser-perl, Ubuntu:20.04:LTS: libxml-parser-perl, Ubuntu:22.04:LTS: libxml-parser-perl, Ubuntu:24.04:LTS: libxml-parser-perl, Ubuntu:25.10: libxml-parser-perl

XML::Parser versions through 2.45 for Perl could overflow the pre-allocated buffer size cause a heap corruption (double free or corruption) and crashes. A :utf8 PerlIO layer, parse_stream() in Expat.xs could overflow the XML input buffer because Perl's read() returns decoded characters while SvPV() gives back multi-byte UTF-8 bytes that can exceed the pre-allocated buffer size. This can cause heap corruption (double free or corruption) and crashes.