CVE Catalog

CVE-2026-64369

Low risk· EPSS 8%
Published: Updated: Translated: NVD NIST

Exploitation Probability (EPSS)

Low risk
0.18%

8th percentile - higher than 8% of all known CVEs

Summary

On s390 architecture, support for DCACHE_WORD_ACCESS was reverted due to exception handling issues with pages donated to the Ultravisor. The load_unaligned_zeropad() function can cause an infinite exception loop.

Risk Assessment

Accessing pages donated to the Ultravisor may cause a system hang due to an infinite exception loop, rendering the system unusable.

Recommendation

Apply the patch that reverts support for DCACHE_WORD_ACCESS as a temporary workaround until a complete fix is available.

Other vulnerabilities in Linux kernel

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Original NVD description (English source)

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

Vulnerability data from NVD (NIST) · CISA KEV · EPSS