Fix two bugs found via fuzzing with AFL++ #4935

Job	Run time
macos-static	2m 29s
unix (ubuntu-22.04, clang++, cmake)	5m 55s
unix (ubuntu-22.04, g++, make)	8m 14s
unix (ubuntu-22.04, clang++, make)	5m 40s
unix (macos-14, clang++, make)	9m 31s
windows (32, windows-2022)	6m 17s
windows (32, windows-2025)	8m 3s
unix (ubuntu-22.04, g++, cmake)	8m 52s
windows (64, windows-2025)	7m 19s
windows (64, windows-2022)	6m 5s
freebsd	4m 48s
windows-mingw-build (64)	1m 16s
unix (macos-14, clang++, cmake)	11m 15s
cygwin (32)	6m 13s
windows-mingw-build (32)	1m 14s
cygwin (64)	6m 15s
windows-mingw-testing (windows-2025, 64)	5m 39s
windows-mingw-testing (windows-2022, 32)	4m 50s
windows-mingw-testing (windows-2022, 64)	5m 11s
windows-mingw-testing (windows-2025, 32)	6m 9s
	2h 1m 15s

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