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CVE-2022-1852 is a moderate-severity NULL-pointer dereference in the Linux kernel's x86 KVM instruction-emulation path. A low-privileged attacker in an Intel-based virtual-machine guest can execute an illegal instruction and trigger a fault in x86_emulate_insn, causing a denial of service. Red Hat assigned a CVSS v3.1 score of 5.5 and classified the defect as CWE-476.
The upstream Linux fix, commit fee060cd52d69c114b62d1a2948ea9648b5131f9, prevents KVM from invoking the x86 emulator before an instruction has been decoded, avoiding use of stale emulation context after breakpoint-related handling. Red Hat released corrected kernel packages for affected RHEL 8 and RHEL 9 systems and related products; RHEL 6 and 7 kernels are not affected. Where patching cannot be performed promptly, Red Hat recommends blacklisting the affected KVM kernel module at boot to prevent it from loading.
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4 events from the most recent confirmed update back to the earliest known activity.
Red Hat released RHSA-2022:7444 for RHEL 8 kernel-rt and RHSA-2022:7683 for the RHEL 8 kernel, addressing the KVM NULL-pointer-dereference denial-of-service vulnerability.
Paolo Bonzini committed Sean Christopherson's patch to prevent x86 KVM instruction emulation from running before an instruction is decoded. The fix was marked for stable-kernel backporting.
Red Hat released RHSA-2024:1877 to fix CVE-2022-1852 for the RHEL 8.6 Extended Update Support kernel and Red Hat Virtualization 4 for RHEL 8.
Red Hat released RHSA-2022:8267 for the RHEL 9 kernel and RHSA-2022:7933 for RHEL 9 kernel-rt to fix CVE-2022-1852.
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**CVE-2022-39189** affects the Linux kernel’s x86 KVM subsystem, where instruction emulation can leave the `KVM_VCPU_PREEMPTED` flag set and mishandle paravirtualized TLB flushes. Other guest vCPUs may then skip required TLB-flush IPIs while emulation accesses memory using stale guest-virtual translations, enabling an unprivileged user inside a VM to compromise the guest kernel or cause guest malfunction. The issue affects the `KVM_FEATURE_PV_TLB_FLUSH` functionality introduced in Linux 4.16 and was demonstrated through emulated VMMCALL and port-I/O operations. The upstream correction, commit `6cd88243c7e03845a450795e134b488fc2afb736`, was merged for Linux 5.19 and backported to the stable 5.15 and 5.18 kernel trees; affected kernels are generally versions before 5.18.17. Red Hat rated the vulnerability Moderate with CVSS 7.0 and issued fixes for affected RHEL 8, RHEL 8 kernel-rt, RHEL 8.6 EUS, RHEL 9, RHEL 9 kernel-rt, and Red Hat Virtualization 4 on RHEL 8 packages; Red Hat reported no qualifying mitigation, making deployment of the relevant kernel updates the required remediation.
Aug 26, 2026
A vulnerability tracked as **CVE-2023-46813** affects the Linux kernel's handling of AMD Secure Encrypted Virtualization (SEV) guests. A low-privileged local user in an SEV virtual machine can use MMIO/string I/O exception-emulation paths to trigger a buffer overflow or null-pointer dereference, potentially causing a denial of service or escalating privileges. Red Hat rates the issue **CVSS 7.0** and categorizes it as improper privilege management (`CWE-269`). Linux fixed the flaw by adding validation in the x86 SEV exception-emulation code before string I/O reads and writes. The new `vc_insn_string_check()` rejects user-space I/O operations whose addresses point into kernel space and raises a user page fault instead. Red Hat issued fixes for affected RHEL 8 and RHEL 9 kernel variants and Red Hat Virtualization 4 on RHEL 8; it reported no generally suitable mitigation beyond applying the relevant updates.
Aug 26, 2026
**CVE-2023-52597** is a low-severity flaw in the Linux kernel's KVM implementation for IBM s390 systems. When KVM uses an ioctl to set a guest vCPU floating-point-unit state, it temporarily loads a floating-point control (FPC) value while validating it; an interrupt that uses floating-point or vector registers during that window can corrupt the host process's FPC register. Red Hat rates the issue CVSS 4.0 (`AV:L/AC:H/PR:N/UI:N/S:U/C:N/I:L/A:L`) and classifies it as improper input validation (CWE-20). Red Hat issued fixes for RHEL 8 `kernel` and `kernel-rt` packages and RHEL 9 `kernel` packages. RHEL 9 `kernel-rt` remained affected at the time of the advisory, while RHEL 6 and RHEL 7 kernel variants were outside support scope. Organizations operating KVM workloads on IBM s390 should identify affected kernel packages and apply the available updates, prioritizing systems where untrusted or highly privileged guest-management operations are permitted.
Aug 26, 2026