cbcvebase.
CVE-2022-50720
published 2025-12-24

CVE-2022-50720: 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…

PriorityP423low4.4
EPSS
0.21%
11.5th percentile
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

Affected

10 ranges
VendorProductVersion rangeFixed in
debianlinux< linux 6.0.3-1 (bookworm)linux 6.0.3-1 (bookworm)
linuxlinux
linuxlinux>= fb209bd891645bb87b9618b724f0b4928e0df3de < 05785ba834f23272f9d23427ae4a80ac505a529605785ba834f23272f9d23427ae4a80ac505a5296
linuxlinux>= fb209bd891645bb87b9618b724f0b4928e0df3de < dd1241e00addbf0b95f6cd6ce32152692820657edd1241e00addbf0b95f6cd6ce32152692820657e
linuxlinux>= fb209bd891645bb87b9618b724f0b4928e0df3de < b8d1d163604bd1e600b062fb00de5dc42baa355fb8d1d163604bd1e600b062fb00de5dc42baa355f
linuxlinux_kernel>= 0 < 6.0.3-16.0.3-1
linuxlinux_kernel>= 0 < 6.0.3-16.0.3-1
linuxlinux_kernel>= 0 < 6.0.3-16.0.3-1
linuxlinux_kernel>= 3.3.0 < 5.19.175.19.17
linuxlinux_kernel>= 5.20.0 < 6.0.36.0.3
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