CVE-2022-50720
x86/apic: Don't disable x2APIC if locked
- Published
- Updated
- Reserved
- Assigned by
- Linux
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
Scores
No CVSS score yet: neither the CNA, CISA nor NVD has scored this CVE. NVD status: Deferred.
- EPSS (exploitation in 30 days)
- 0.24% · top 85% of all CVEs (6 Nov 2026)
The list uses the assigner's score when there is one, then CISA's, then NVD's: Not scored.
Affected products
- affected fb209bd891645bb87b9618b724f0b4928e0df3de – < 05785ba834f23272f9d23427ae4a80ac505a5296
- affected fb209bd891645bb87b9618b724f0b4928e0df3de – < dd1241e00addbf0b95f6cd6ce32152692820657e
- affected fb209bd891645bb87b9618b724f0b4928e0df3de – < b8d1d163604bd1e600b062fb00de5dc42baa355f
- affected 3.3
- unaffected < 3.3
- unaffected 5.19.17 – ≤ 5.19.*
- unaffected 6.0.3 – ≤ 6.0.*
- unaffected 6.1 – ≤ *
References (3)
Sources
The same CVE in the primary databases and aggregators, to check against.
- CVE.org record (opens in a new tab)
- CVE List JSON (GitHub) (opens in a new tab)
- NVD (opens in a new tab)
- FIRST EPSS (opens in a new tab)
- OSV.dev (opens in a new tab)
- GitHub Advisories (opens in a new tab)
- CIRCL Vulnerability-Lookup (opens in a new tab)
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[](https://trackcve.app/cve/CVE-2022-50720)Record last updated .