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CVE-2021-47553

7.8 · HIGH
Published May 24, 2024 linux CWE-908 EPSS 0.26% (17th pctl)

Overview

CVE-2021-47553 is a high-severity vulnerability affecting linux linux_kernel. It was published on May 24, 2024 and has a CVSS 3.1 base score of 7.8 (HIGH).

This vulnerability has a CVSS 3.1 base score of 7.8, rated HIGH. 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:

sched/scs: Reset task stack state in bringup_cpu()

To hot unplug a CPU, the idle task on that CPU calls a few layers of C

code before finally leaving the kernel. When KASAN is in use, poisoned

shadow is left around for each of the active stack frames, and when

shadow call stacks are in use. When shadow call stacks (SCS) are in use

the task's saved SCS SP is left pointing at an arbitrary point within

the task's shadow call stack.

When a CPU is offlined than onlined back into the kernel, this stale

state can adversely affect execution. Stale KASAN shadow can alias new

stackframes and result in bogus KASAN warnings. A stale SCS SP is

effectively a memory leak, and prevents a portion of the shadow call

stack being used. Across a number of hotplug cycles the idle task's

entire shadow call stack can become unusable.

We previously fixed the KASAN issue in commit:

e1b77c92981a5222 ("sched/kasan: remove stale KASAN poiso

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 >= 5.10.50, < 5.10.83 Affected

Frequently Asked Questions

What is CVE-2021-47553?

CVE-2021-47553 is a high-severity vulnerability affecting linux linux_kernel. It was published on May 24, 2024 and has a CVSS 3.1 base score of 7.8 (HIGH).

How severe is CVE-2021-47553?

This vulnerability has a CVSS 3.1 base score of 7.8, rated HIGH. It requires local or adjacent network access to exploit. Some level of privileges is required for exploitation.

How do I fix or remediate CVE-2021-47553?

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-2021-47553?

CyberStrike's AI-powered security agents can automatically detect CVE-2021-47553 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.