CVE-2025-21632
5.5 · MEDIUMOverview
CVE-2025-21632 is a medium-severity vulnerability affecting linux linux_kernel. It was published on January 19, 2025 and has a CVSS 3.1 base score of 5.5 (MEDIUM).
This vulnerability has a CVSS 3.1 base score of 5.5, rated MEDIUM. It requires local or adjacent network access to exploit. Some level of privileges is required for exploitation.
Technical Description
In the Linux kernel, the following vulnerability has been resolved:
x86/fpu: Ensure shadow stack is active before "getting" registers
The x86 shadow stack support has its own set of registers. Those registers
are XSAVE-managed, but they are "supervisor state components" which means
that userspace can not touch them with XSAVE/XRSTOR. It also means that
they are not accessible from the existing ptrace ABI for XSAVE state.
Thus, there is a new ptrace get/set interface for it.
The regset code that ptrace uses provides an ->active() handler in
addition to the get/set ones. For shadow stack this ->active() handler
verifies that shadow stack is enabled via the ARCH_SHSTK_SHSTK bit in the
thread struct. The ->active() handler is checked from some call sites of
the regset get/set handlers, but not the ptrace ones. This was not
understood when shadow stack support was put in place.
As a result, both the set/get handlers can be called with
XFEATURE_CET_USER in its init state, which would ca
Remediation
Check the references section for vendor advisories and patches from linux. Update linux_kernel to the latest patched version. If immediate patching is not possible, review the CVSS vector to understand the attack surface and apply compensating controls such as network segmentation or access restrictions.
Affected Products
| Vendor | Product | Versions | Status |
|---|---|---|---|
| linux | linux_kernel | >= 6.6, < 6.6.72 | Affected |
Frequently Asked Questions
What is CVE-2025-21632?
CVE-2025-21632 is a medium-severity vulnerability affecting linux linux_kernel. It was published on January 19, 2025 and has a CVSS 3.1 base score of 5.5 (MEDIUM).
How severe is CVE-2025-21632?
This vulnerability has a CVSS 3.1 base score of 5.5, rated MEDIUM. It requires local or adjacent network access to exploit. Some level of privileges is required for exploitation.
How do I fix or remediate CVE-2025-21632?
Check the references section for vendor advisories and patches from linux. Update linux_kernel to the latest patched version. If immediate patching is not possible, review the CVSS vector to understand the attack surface and apply compensating controls such as network segmentation or access restrictions.
How can CyberStrike help with CVE-2025-21632?
CyberStrike's AI-powered security agents can automatically detect CVE-2025-21632 across your infrastructure using autonomous pentesting, DAST scanning, and HackBrowser. The platform continuously monitors for known vulnerabilities and provides actionable remediation guidance prioritized by real-world exploitability.
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