re2c 1.3 has a heap-based buffer overflow in Scanner::fill in parse/scanner.cc via a long lexeme.
https://www.openwall.com/lists/oss-security/2020/04/19/1
https://usn.ubuntu.com/4338-2/
https://usn.ubuntu.com/4338-1/
https://security.gentoo.org/glsa/202007-28
https://github.com/skvadrik/re2c/commit/c4603ba5ce229db83a2a4fb93e6d4b4e3ec3776a
https://blogs.gentoo.org/ago/2020/04/19/re2c-heap-overflow-in-scannerfill-scanner-cc/