# CVE-2026-46295: linux: In the Linux kernel, the following vulnerability has been resolved: KVM: x86: Do IRR scan in __kvm_apic_update_irr e... CVE-2026-46295 is fixed in 19 products on 1 platform, first by ALAS2023-2026-1754, released May 25, 2026. It is not reported as exploited. Patch Radar priority: Routine. - Web page: https://patchblox.com/security/cve/CVE-2026-46295 - Priority: Routine - CVSS: 5.5 (medium) - EPSS: 0.0011 - CISA KEV: not listed - Exploited (vendor report): no - Publicly disclosed: no - Published: May 25, 2026 ## Description In the Linux kernel, the following vulnerability has been resolved: KVM: x86: Do IRR scan in __kvm_apic_update_irr even if PIR is empty Fall back to apic_find_highest_vector() when PID.ON is set but PIR turns out to be empty, to correctly report the highest pending interrupt from the existing IRR. In a nested VM stress test, the following WARNING fires in vmx_check_nested_events() when kvm_cpu_has_interrupt() reports a pending interrupt but the subsequent kvm_apic_has_interrupt() (which invokes vmx_sync_pir_to_irr() again) returns -1: WARNING: CPU: 99 PID: 57767 at arch/x86/kvm/vmx/nested.c:4449 vmx_check_nested_events+0x6bf/0x6e0 [kvm_intel] Call Trace: kvm_check_and_inject_events vcpu_enter_guest.constprop.0 vcpu_run kvm_arch_vcpu_ioctl_run kvm_vcpu_ioctl __x64_sys_ioctl do_syscall_64 entry_SYSCALL_64_after_hwframe The root cause is a race between vmx_sync_pir_to_irr() on the target vCPU and __vmx_deliver_posted_interrupt() on a sender vCPU. The sender performs two individually-atomic operations that are not a single transaction: 1. pi_test_and_set_pir(vector) -- sets the PIR bit 2. pi_test_and_set_on() -- sets PID.ON The following interleaving triggers the bug: Sender vCPU (IPI): Target vCPU (1st sync_pir_to_irr): B1: set PIR[vector] A1: pi_clear_on() A2: pi_harvest_pir() -> sees B1 bit A3: xchg() -> consumes bit, PIR=0 (1st sync returns correct max_irr) B2: set PID.ON = 1 Target vCPU (2nd sync_pir_to_irr): C1: pi_test_on() -> TRUE (from B2) C2: pi_clear_on() -> ON=0 C3: pi_harvest_pir() -> PIR empty C4: *max_irr = -1, early return IRR NOT SCANNED The interrupt is not lost (it resides in the IRR from the first sync and is recovered on the next vcpu_enter_guest() iteration), but the incorrect max_irr causes a spurious WARNING and a wasted L2 VM-Enter/VM-Exit cycle. ## Where it's fixed | Platform | Product | Fixed in | Fix | Released | |---|---|---|---|---| | Linux | bpftool6.18 amzn 2023 | 1:6.18.30-61.116.amzn2023 | [ALAS2023-2026-1754](https://patchblox.com/security/data/fix/linux/alas2023-2026-1754.md) | May 25, 2026 | | Linux | bpftool6.18-debuginfo amzn 2023 | 1:6.18.30-61.116.amzn2023 | [ALAS2023-2026-1754](https://patchblox.com/security/data/fix/linux/alas2023-2026-1754.md) | May 25, 2026 | | Linux | kernel-livepatch-6.18.30-61.116 amzn 2023 | 1:1.0-0.amzn2023 | [ALAS2023-2026-1754](https://patchblox.com/security/data/fix/linux/alas2023-2026-1754.md) | May 25, 2026 | | Linux | kernel6.18 amzn 2023 | 1:6.18.30-61.116.amzn2023 | [ALAS2023-2026-1754](https://patchblox.com/security/data/fix/linux/alas2023-2026-1754.md) | May 25, 2026 | | Linux | kernel6.18-debuginfo amzn 2023 | 1:6.18.30-61.116.amzn2023 | [ALAS2023-2026-1754](https://patchblox.com/security/data/fix/linux/alas2023-2026-1754.md) | May 25, 2026 | | Linux | kernel6.18-debuginfo-common-aarch64 amzn 2023 | 1:6.18.30-61.116.amzn2023 | [ALAS2023-2026-1754](https://patchblox.com/security/data/fix/linux/alas2023-2026-1754.md) | May 25, 2026 | | Linux | kernel6.18-debuginfo-common-x86_64 amzn 2023 | 1:6.18.30-61.116.amzn2023 | [ALAS2023-2026-1754](https://patchblox.com/security/data/fix/linux/alas2023-2026-1754.md) | May 25, 2026 | | Linux | kernel6.18-devel amzn 2023 | 1:6.18.30-61.116.amzn2023 | [ALAS2023-2026-1754](https://patchblox.com/security/data/fix/linux/alas2023-2026-1754.md) | May 25, 2026 | | Linux | kernel6.18-headers amzn 2023 | 1:6.18.30-61.116.amzn2023 | [ALAS2023-2026-1754](https://patchblox.com/security/data/fix/linux/alas2023-2026-1754.md) | May 25, 2026 | | Linux | kernel6.18-modules-extra amzn 2023 | 1:6.18.30-61.116.amzn2023 | [ALAS2023-2026-1754](https://patchblox.com/security/data/fix/linux/alas2023-2026-1754.md) | May 25, 2026 | | Linux | kernel6.18-modules-extra-common amzn 2023 | 1:6.18.30-61.116.amzn2023 | [ALAS2023-2026-1754](https://patchblox.com/security/data/fix/linux/alas2023-2026-1754.md) | May 25, 2026 | | Linux | kernel6.18-tools amzn 2023 | 1:6.18.30-61.116.amzn2023 | [ALAS2023-2026-1754](https://patchblox.com/security/data/fix/linux/alas2023-2026-1754.md) | May 25, 2026 | | Linux | kernel6.18-tools-debuginfo amzn 2023 | 1:6.18.30-61.116.amzn2023 | [ALAS2023-2026-1754](https://patchblox.com/security/data/fix/linux/alas2023-2026-1754.md) | May 25, 2026 | | Linux | kernel6.18-tools-devel amzn 2023 | 1:6.18.30-61.116.amzn2023 | [ALAS2023-2026-1754](https://patchblox.com/security/data/fix/linux/alas2023-2026-1754.md) | May 25, 2026 | | Linux | linux Debian 14 | 7.0.7-1 | [DEBIAN-CVE-2026-46295](https://patchblox.com/security/data/fix/linux/debian-cve-2026-46295.md) | Jun 24, 2026 | | Linux | perf6.18 amzn 2023 | 1:6.18.30-61.116.amzn2023 | [ALAS2023-2026-1754](https://patchblox.com/security/data/fix/linux/alas2023-2026-1754.md) | May 25, 2026 | | Linux | perf6.18-debuginfo amzn 2023 | 1:6.18.30-61.116.amzn2023 | [ALAS2023-2026-1754](https://patchblox.com/security/data/fix/linux/alas2023-2026-1754.md) | May 25, 2026 | | Linux | python3-perf6.18 amzn 2023 | 1:6.18.30-61.116.amzn2023 | [ALAS2023-2026-1754](https://patchblox.com/security/data/fix/linux/alas2023-2026-1754.md) | May 25, 2026 | | Linux | python3-perf6.18-debuginfo amzn 2023 | 1:6.18.30-61.116.amzn2023 | [ALAS2023-2026-1754](https://patchblox.com/security/data/fix/linux/alas2023-2026-1754.md) | May 25, 2026 | --- Data as of 2026-11-08T19:12:23Z UTC. Source: Patchblox Patch Radar (https://patchblox.com/security/patch-radar). Patchblox finds out-of-date software on Windows, macOS and Linux and updates it through release rings: https://patchblox.com/demo Free to use with attribution: show "Data: Patchblox Patch Radar" with a link to https://patchblox.com/security/patch-radar. Terms, including what needs a written agreement: https://patchblox.com/security/patch-radar/use-the-data Product names, logos and trademarks shown on Patch Radar belong to their respective owners. They are used only to identify the software each security fix applies to and to help readers find their platform. Their use does not imply any affiliation with, or endorsement by, those owners, and Patchblox is not affiliated with any of them.