Affected: TODDR XML::Parser, Red Hat Enterprise Linux 10, Red Hat Enterprise Linux 10.0 Extended Update Support, Red Hat Enterprise Linux 7 Extended Lifecycle Support, Red Hat Enterprise Linux 8, Red Hat Enterprise Linux 8.2 Advanced Update Support, Red Hat Enterprise Linux 8.4 Advanced Mission Critical Update Support, Red Hat Enterprise Linux 8.4 Extended Update Support Long-Life Add-On, Red Hat Enterprise Linux 8.6 Advanced Mission Critical Update Support, Red Hat Enterprise Linux 8.6 Telecommunications Update Service and 9 more

XML::Parser versions through 2.47 for Perl has an off-by-one heap buffer overflow in st_serial_stack.

In the case (stackptr == stacksize - 1), the stack will NOT be expanded. Then the new value will be written at location (++stackptr), which equals stacksize and therefore falls just outside the allocated buffer.

The bug can be observed when parsing an XML file with very deep element nesting