# CVE-2022-50720: x86/apic: Don't disable x2APIC if locked

> Local attackers can exploit APIC MMIO interface to extract data from SGX enclaves if x2APIC is not locked by BIOS.

- **Severity:** Not scored
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Local or same network only
- **Victim action needed:** Not needed
- **Fix available:** Yes
- **Published:** 24 Dec 2025
- **Updated:** 11 May 2026
- **Also known as:** DEBIAN-CVE-2022-50720, GHSA-pc73-7j79-5x2x, ROOT-OS-DEBIAN-11-CVE-2022-50720, ROOT-OS-UBUNTU-2204-CVE-2022-50720, UBUNTU-CVE-2022-50720

## What is CVE-2022-50720?

CVE-2022-50720 is a vulnerability in Linux, published on 24 Dec 2025. It can only be exploited from the same machine or local network, with no action from the victim.

### Official description

In the Linux kernel, the following vulnerability has been resolved:

x86/apic: Don't disable x2APIC if locked

The APIC supports two modes, legacy APIC (or xAPIC), and Extended APIC
(or x2APIC).  X2APIC mode is mostly compatible with legacy APIC, but
it disables the memory-mapped APIC interface in favor of one that uses
MSRs.  The APIC mode is controlled by the EXT bit in the APIC MSR.

The MMIO/xAPIC interface has some problems, most notably the APIC LEAK
[1].  This bug allows an attacker to use the APIC MMIO interface to
extract data from the SGX enclave.

Introduce support for a new feature that will allow the BIOS to lock
the APIC in x2APIC mode.  If the APIC is locked in x2APIC mode and the
kernel tries to disable the APIC or revert to legacy APIC mode a GP
fault will occur.

Introduce support for a new MSR (IA32_XAPIC_DISABLE_STATUS) and handle
the new locked mode when the LEGACY_XAPIC_DISABLED bit is set by
preventing the kernel from trying to disable the x2APIC.

On platforms with the IA32_XAPIC_DISABLE_STATUS MSR, if SGX or TDX are
enabled the LEGACY_XAPIC_DISABLED will be set by the BIOS.  If
legacy APIC is required, then it SGX and TDX need to be disabled in the
BIOS.

[1]: https://aepicleak.com/aepicleak.pdf

## Which versions are affected by CVE-2022-50720?


## How do I fix CVE-2022-50720?

Apply the vendor's patch.

## Is CVE-2022-50720 being exploited?

There is no known exploitation of CVE-2022-50720 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2022-50720 and fix it if it is affected.

What it is: CVE-2022-50720 is a vulnerability in Linux, published on 24 Dec 2025. It can only be exploited from the same machine or local network, with no action from the victim.
Exploitation: There is no known exploitation of CVE-2022-50720 in the wild and no public exploit code.

Affected product: Linux. No package-level version data is available, so check the vendor advisory linked from the reference page.

Task:
1. Search the dependency manifests and lockfiles (for example package.json, package-lock.json, requirements.txt, poetry.lock, uv.lock, pom.xml, build.gradle, go.mod, Cargo.lock, Gemfile.lock) and any Dockerfiles for the affected packages, including transitive dependencies.
2. If an affected version is in use, upgrade it to the fixed version for its release line with the project's package manager, so the lockfile is regenerated. Prefer the smallest upgrade that fixes it.
3. If there is no fix, or the upgrade would break the build, do not guess: explain the risk and the safest workaround instead.
4. Run the tests and summarise what changed and why.
5. If nothing in the project is affected, say so and change nothing.

Reference: https://insights.sbomify.com/CVE-2022-50720/ (Markdown: https://insights.sbomify.com/CVE-2022-50720/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2022-50720
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2022-50720
- OSV: https://osv.dev/vulnerability/CVE-2022-50720

---
From sbomify Insights: https://insights.sbomify.com/CVE-2022-50720/
Summaries are generated and may contain mistakes; the official description above is the record.