CVE-2026-64369

In the Linux kernel, the following vulnerability has been resolved:<br /> <br /> s390: Revert support for DCACHE_WORD_ACCESS<br /> <br /> load_unaligned_zeropad() reads eight bytes from unaligned addresses and may<br /> cross page boundaries. It handles exceptions which may happen if reading<br /> from the second page results in an exception.<br /> <br /> For pages which are donated to the Ultravisor for secure execution purposes<br /> the do_secure_storage_access() exception handler however does not handle<br /> such exceptions correctly. Such an exception may result in an endless<br /> exception loop which will never be resolved.<br /> <br /> An attempt to fix this [1] turned out to be not sufficient. For now revert<br /> load_unaligned_zeropad() until this problem has been resolved in a proper<br /> way.<br /> <br /> Note that the implementation of load_unaligned_zeropad() itself is<br /> correct. The revert is just a temporary workaround until there is complete<br /> fix for secure storage access exceptions.<br /> <br /> [1] commit b00be77302d7 ("s390/mm: Add missing secure storage access fixups for donated memory")