kernel-4.18.0-553.147.1.el8_10

CVE-2025-40026
In the Linux kernel, the following vulnerability has been resolved: KVM: x86: Don't (re)check L1 intercepts when completing userspace I/O When completing emulation of instruction that generated a userspace exit for I/O, don't recheck L1 intercepts as KVM has already finished that phase of instruction execution, i.e. has already committed to allowing L2 to perform I/O. If L1 (or host userspace) modifies the I/O permission bitmaps during the exit to userspace, KVM will treat the access as being intercepted despite already having emulated the I/O access. Pivot on EMULTYPE_NO_DECODE to detect that KVM is completing emulation. Of the three users of EMULTYPE_NO_DECODE, only complete_emulated_io() (the intended "recipient") can reach the code in question. gp_interception()'s use is mutually exclusive with is_guest_mode(), and complete_emulated_insn_gp() unconditionally pairs EMULTYPE_NO_DECODE with EMULTYPE_SKIP. The bad behavior was detected by a syzkaller program that toggles port I/O interception during the userspace I/O exit, ultimately resulting in a WARN on vcpu->arch.pio.count being non-zero due to KVM no completing emulation of the I/O instruction. WARNING: CPU: 23 PID: 1083 at arch/x86/kvm/x86.c:8039 emulator_pio_in_out+0x154/0x170 [kvm] Modules linked in: kvm_intel kvm irqbypass CPU: 23 UID: 1000 PID: 1083 Comm: repro Not tainted 6.16.0-rc5-c1610d2d66b1-next-vm #74 NONE Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 0.0.0 02/06/2015 RIP: 0010:emulator_pio_in_out+0x154/0x170 [kvm] PKRU: 55555554 Call Trace: <TASK> kvm_fast_pio+0xd6/0x1d0 [kvm] vmx_handle_exit+0x149/0x610 [kvm_intel] kvm_arch_vcpu_ioctl_run+0xda8/0x1ac0 [kvm] kvm_vcpu_ioctl+0x244/0x8c0 [kvm] __x64_sys_ioctl+0x8a/0xd0 do_syscall_64+0x5d/0xc60 entry_SYSCALL_64_after_hwframe+0x4b/0x53 </TASK>

CVE-2026-53059
In the Linux kernel, the following vulnerability has been resolved: dm log: fix out-of-bounds write due to region_count overflow The local variable region_count in create_log_context() is declared as unsigned int (32-bit), but dm_sector_div_up() returns sector_t (64-bit). When a device-mapper target has a sufficiently large ti->len with a small region_size, the division result can exceed UINT_MAX. The truncated value is then used to calculate bitset_size, causing clean_bits, sync_bits, and recovering_bits to be allocated far smaller than needed for the actual number of regions. Subsequent log operations (log_set_bit, log_clear_bit, log_test_bit) use region indices derived from the full untruncated region space, causing out-of-bounds writes to kernel heap memory allocated by vmalloc. This can be reproduced by creating a mirror target whose region_count overflows 32 bits: dmsetup create bigzero --table '0 8589934594 zero' dmsetup create mymirror --table '0 8589934594 mirror \ core 2 2 nosync 2 /dev/mapper/bigzero 0 \ /dev/mapper/bigzero 0' The status output confirms the truncation (sync_count=1 instead of 4294967297, because 0x100000001 was truncated to 1): $ dmsetup status mymirror 0 8589934594 mirror 2 254:1 254:1 1/4294967297 ... This leads to a kernel crash in core_in_sync: BUG: scheduling while atomic: (udev-worker)/9150/0x00000000 RIP: 0010:core_in_sync+0x14/0x30 [dm_log] CR2: 0000000000000008 Fixing recursive fault but reboot is needed! Fix by widening the local region_count to sector_t and adding an explicit overflow check before the value is assigned to lc->region_count.