Bug 2481913 (CVE-2026-45876)

Summary: CVE-2026-45876 kernel: arm64/gcs: Fix error handling in arch_set_shadow_stack_status()
Product: [Other] Security Response Reporter: OSIDB Bzimport <bzimport>
Component: vulnerabilityAssignee: Product Security <prodsec-ir-bot>
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Priority: low    
Version: unspecifiedCC: rhel-process-autobot, watson-tool-maintainers
Target Milestone: ---Keywords: Security
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Hardware: All   
OS: Linux   
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Doc Text:
A flaw was found in the Linux kernel. Improper error handling in the `arch_set_shadow_stack_status()` function, specifically related to `alloc_gcs()`, could lead to the use of an invalid Global Context Structure (GCS) address. This issue may allow a local attacker to cause system instability or a denial of service.
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Description OSIDB Bzimport 2026-05-27 15:02:03 UTC 
In the Linux kernel, the following vulnerability has been resolved:

arm64/gcs: Fix error handling in arch_set_shadow_stack_status()

alloc_gcs() returns an error-encoded pointer on failure, which comes
from do_mmap(), not NULL.

The current NULL check fails to detect errors, which could lead to using
an invalid GCS address.

Use IS_ERR_VALUE() to properly detect errors, consistent with the
check in gcs_alloc_thread_stack().
Comment 1 Keith Grant 2026-05-28 03:30:45 UTC 
Upstream advisory:
https://lore.kernel.org/linux-cve-announce/2026052714-CVE-2026-45876-4460@gregkh/T