An issue was discovered in GNU gettext 0.19.8. There is a double free in default_add_message in read-catalog.c, related to an invalid free in po_gram_parse in po-gram-gen.y, as demonstrated by lt-msgfmt.
lists.opensuse.org/opensuse-security-announce/2020-08/msg00061.html
lists.opensuse.org/opensuse-security-announce/2020-08/msg00065.html
lists.opensuse.org/opensuse-security-announce/2020-09/msg00025.html
access.redhat.com/errata/RHSA-2019:3643
github.com/CCCCCrash/POCs/tree/master/Bin/Tools-gettext-0.19.8.1/doublefree
github.com/CCCCCrash/POCs/tree/master/Bin/Tools-gettext-0.19.8.1/heapcorruption
usn.ubuntu.com/3815-1/
usn.ubuntu.com/3815-2/