In the Linux kernel, the following vulnerability has been resolved: s390: Revert support for DCACHE_WORD_ACCESS load_unaligned_zeropad() reads eight… (CVE-2026-64369)
A vulnerability in the Linux kernel's s390 architecture involves the load_unaligned_zeropad() function, which reads eight bytes from unaligned addresses and may cross page boundaries. When pages are donated to the Ultravisor for secure execution, exceptions triggered by these reads are not handled correctly by the do_secure_storage_access() exception handler, potentially causing an endless exception loop. The issue was temporarily mitigated by reverting the load_unaligned_zeropad() support until a proper fix is developed. The function's implementation itself is correct; the revert is a workaround for incomplete exception handling in secure storage access.
AI Analysis
Technical Summary
The Linux kernel vulnerability CVE-2026-64369 affects the s390 architecture's load_unaligned_zeropad() function, which reads eight bytes from potentially unaligned addresses crossing page boundaries. For memory pages donated to the Ultravisor for secure execution, exceptions caused by these reads are not properly handled by the do_secure_storage_access() exception handler, leading to an endless exception loop. An initial fix was insufficient, so the kernel reverted the load_unaligned_zeropad() support as a temporary workaround until a comprehensive fix for secure storage access exceptions is implemented. The vulnerability does not stem from the function's implementation but from incomplete exception handling in the secure storage context.
Potential Impact
If triggered, this vulnerability can cause an endless exception loop in the kernel on s390 systems when accessing secure storage memory pages, potentially leading to system instability or denial of service conditions. There is no indication of remote code execution or data leakage from the provided information.
Mitigation Recommendations
A temporary workaround has been applied by reverting the load_unaligned_zeropad() support in the Linux kernel for s390 architecture. Users should apply this kernel update that includes the revert. A complete fix is pending and will address proper exception handling for secure storage access. Monitor vendor advisories for updates and apply official patches once available.
In the Linux kernel, the following vulnerability has been resolved: s390: Revert support for DCACHE_WORD_ACCESS load_unaligned_zeropad() reads eight… (CVE-2026-64369)
Description
A vulnerability in the Linux kernel's s390 architecture involves the load_unaligned_zeropad() function, which reads eight bytes from unaligned addresses and may cross page boundaries. When pages are donated to the Ultravisor for secure execution, exceptions triggered by these reads are not handled correctly by the do_secure_storage_access() exception handler, potentially causing an endless exception loop. The issue was temporarily mitigated by reverting the load_unaligned_zeropad() support until a proper fix is developed. The function's implementation itself is correct; the revert is a workaround for incomplete exception handling in secure storage access.
AI-Powered Analysis
Machine-generated threat intelligence
Technical Analysis
The Linux kernel vulnerability CVE-2026-64369 affects the s390 architecture's load_unaligned_zeropad() function, which reads eight bytes from potentially unaligned addresses crossing page boundaries. For memory pages donated to the Ultravisor for secure execution, exceptions caused by these reads are not properly handled by the do_secure_storage_access() exception handler, leading to an endless exception loop. An initial fix was insufficient, so the kernel reverted the load_unaligned_zeropad() support as a temporary workaround until a comprehensive fix for secure storage access exceptions is implemented. The vulnerability does not stem from the function's implementation but from incomplete exception handling in the secure storage context.
Potential Impact
If triggered, this vulnerability can cause an endless exception loop in the kernel on s390 systems when accessing secure storage memory pages, potentially leading to system instability or denial of service conditions. There is no indication of remote code execution or data leakage from the provided information.
Mitigation Recommendations
A temporary workaround has been applied by reverting the load_unaligned_zeropad() support in the Linux kernel for s390 architecture. Users should apply this kernel update that includes the revert. A complete fix is pending and will address proper exception handling for secure storage access. Monitor vendor advisories for updates and apply official patches once available.
Technical Details
- Gcve Source
- db.gcve.eu
- Osv Id
- GHSA-ww8w-mgxm-5cf5
- Osv Schema Version
- 1.4.0
- Aliases
- ["CVE-2026-64369"]
- Ecosystems
- []
- Database Specific Severity
- null
- Cvss Version
- null
Threat ID: 6a65420a9c2644c7f8084448
Added to database: 07/25/2026, 23:08:58 UTC
Last enriched: 07/25/2026, 23:27:37 UTC
Last updated: 07/26/2026, 05:13:55 UTC
Views: 5
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