{"dataType": "CVE_RECORD", "dataVersion": "5.2", "cveMetadata": {"cveId": "CVE-2025-40274", "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "state": "PUBLISHED", "assignerShortName": "Linux", "dateReserved": "2025-04-16T07:20:57.184Z", "datePublished": "2025-12-06T21:50:56.832Z", "dateUpdated": "2025-12-06T21:50:56.832Z"}, "containers": {"cna": {"providerMetadata": {"orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "shortName": "Linux", "dateUpdated": "2025-12-06T21:50:56.832Z"}, "descriptions": [{"lang": "en", "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nKVM: guest_memfd: Remove bindings on memslot deletion when gmem is dying\n\nWhen unbinding a memslot from a guest_memfd instance, remove the bindings\neven if the guest_memfd file is dying, i.e. even if its file refcount has\ngone to zero. If the memslot is freed before the file is fully released,\nnullifying the memslot side of the binding in kvm_gmem_release() will\nwrite to freed memory, as detected by syzbot+KASAN:\n\n ==================================================================\n BUG: KASAN: slab-use-after-free in kvm_gmem_release+0x176/0x440 virt/kvm/guest_memfd.c:353\n Write of size 8 at addr ffff88807befa508 by task syz.0.17/6022\n\n CPU: 0 UID: 0 PID: 6022 Comm: syz.0.17 Not tainted syzkaller #0 PREEMPT(full)\n Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/02/2025\n Call Trace:\n <TASK>\n dump_stack_lvl+0x189/0x250 lib/dump_stack.c:120\n print_address_description mm/kasan/report.c:378 [inline]\n print_report+0xca/0x240 mm/kasan/report.c:482\n kasan_report+0x118/0x150 mm/kasan/report.c:595\n kvm_gmem_release+0x176/0x440 virt/kvm/guest_memfd.c:353\n __fput+0x44c/0xa70 fs/file_table.c:468\n task_work_run+0x1d4/0x260 kernel/task_work.c:227\n resume_user_mode_work include/linux/resume_user_mode.h:50 [inline]\n exit_to_user_mode_loop+0xe9/0x130 kernel/entry/common.c:43\n exit_to_user_mode_prepare include/linux/irq-entry-common.h:225 [inline]\n syscall_exit_to_user_mode_work include/linux/entry-common.h:175 [inline]\n syscall_exit_to_user_mode include/linux/entry-common.h:210 [inline]\n do_syscall_64+0x2bd/0xfa0 arch/x86/entry/syscall_64.c:100\n entry_SYSCALL_64_after_hwframe+0x77/0x7f\n RIP: 0033:0x7fbeeff8efc9\n </TASK>\n\n Allocated by task 6023:\n kasan_save_stack mm/kasan/common.c:56 [inline]\n kasan_save_track+0x3e/0x80 mm/kasan/common.c:77\n poison_kmalloc_redzone mm/kasan/common.c:397 [inline]\n __kasan_kmalloc+0x93/0xb0 mm/kasan/common.c:414\n kasan_kmalloc include/linux/kasan.h:262 [inline]\n __kmalloc_cache_noprof+0x3e2/0x700 mm/slub.c:5758\n kmalloc_noprof include/linux/slab.h:957 [inline]\n kzalloc_noprof include/linux/slab.h:1094 [inline]\n kvm_set_memory_region+0x747/0xb90 virt/kvm/kvm_main.c:2104\n kvm_vm_ioctl_set_memory_region+0x6f/0xd0 virt/kvm/kvm_main.c:2154\n kvm_vm_ioctl+0x957/0xc60 virt/kvm/kvm_main.c:5201\n vfs_ioctl fs/ioctl.c:51 [inline]\n __do_sys_ioctl fs/ioctl.c:597 [inline]\n __se_sys_ioctl+0xfc/0x170 fs/ioctl.c:583\n do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]\n do_syscall_64+0xfa/0xfa0 arch/x86/entry/syscall_64.c:94\n entry_SYSCALL_64_after_hwframe+0x77/0x7f\n\n Freed by task 6023:\n kasan_save_stack mm/kasan/common.c:56 [inline]\n kasan_save_track+0x3e/0x80 mm/kasan/common.c:77\n kasan_save_free_info+0x46/0x50 mm/kasan/generic.c:584\n poison_slab_object mm/kasan/common.c:252 [inline]\n __kasan_slab_free+0x5c/0x80 mm/kasan/common.c:284\n kasan_slab_free include/linux/kasan.h:234 [inline]\n slab_free_hook mm/slub.c:2533 [inline]\n slab_free mm/slub.c:6622 [inline]\n kfree+0x19a/0x6d0 mm/slub.c:6829\n kvm_set_memory_region+0x9c4/0xb90 virt/kvm/kvm_main.c:2130\n kvm_vm_ioctl_set_memory_region+0x6f/0xd0 virt/kvm/kvm_main.c:2154\n kvm_vm_ioctl+0x957/0xc60 virt/kvm/kvm_main.c:5201\n vfs_ioctl fs/ioctl.c:51 [inline]\n __do_sys_ioctl fs/ioctl.c:597 [inline]\n __se_sys_ioctl+0xfc/0x170 fs/ioctl.c:583\n do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]\n do_syscall_64+0xfa/0xfa0 arch/x86/entry/syscall_64.c:94\n entry_SYSCALL_64_after_hwframe+0x77/0x7f\n\nDeliberately don't acquire filemap invalid lock when the file is dying as\nthe lifecycle of f_mapping is outside the purview of KVM. Dereferencing\nthe mapping is *probably* fine, but there's no need to invalidate anything\nas memslot deletion is responsible for zapping SPTEs, and the only code\nthat can access the dying file is kvm_gmem_release(), whose core code is\nmutual\n---truncated---"}], "affected": [{"product": "Linux", "vendor": "Linux", "defaultStatus": "unaffected", "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "programFiles": ["virt/kvm/guest_memfd.c"], "versions": [{"version": "a7800aa80ea4d5356b8474c2302812e9d4926fa6", "lessThan": "a8ac2bd0f98e1a230f1eb3260fa552bf2ef1753b", "status": "affected", "versionType": "git"}, {"version": "a7800aa80ea4d5356b8474c2302812e9d4926fa6", "lessThan": "393893693a523e053f84d69320d090b93503f79f", "status": "affected", "versionType": "git"}, {"version": "a7800aa80ea4d5356b8474c2302812e9d4926fa6", "lessThan": "ae431059e75d36170a5ae6b44cc4d06d43613215", "status": "affected", "versionType": "git"}]}, {"product": "Linux", "vendor": "Linux", "defaultStatus": "affected", "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "programFiles": ["virt/kvm/guest_memfd.c"], "versions": [{"version": "6.8", "status": "affected"}, {"version": "0", "lessThan": "6.8", "status": "unaffected", "versionType": "semver"}, {"version": "6.12.59", "lessThanOrEqual": "6.12.*", "status": "unaffected", "versionType": "semver"}, {"version": "6.17.9", "lessThanOrEqual": "6.17.*", "status": "unaffected", "versionType": "semver"}, {"version": "6.18", "lessThanOrEqual": "*", "status": "unaffected", "versionType": "original_commit_for_fix"}]}], "cpeApplicability": [{"nodes": [{"operator": "OR", "negate": false, "cpeMatch": [{"vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "6.8", "versionEndExcluding": "6.12.59"}, {"vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "6.8", "versionEndExcluding": "6.17.9"}, {"vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "6.8", "versionEndExcluding": "6.18"}]}]}], "references": [{"url": "https://git.kernel.org/stable/c/a8ac2bd0f98e1a230f1eb3260fa552bf2ef1753b"}, {"url": "https://git.kernel.org/stable/c/393893693a523e053f84d69320d090b93503f79f"}, {"url": "https://git.kernel.org/stable/c/ae431059e75d36170a5ae6b44cc4d06d43613215"}], "title": "KVM: guest_memfd: Remove bindings on memslot deletion when gmem is dying", "x_generator": {"engine": "bippy-1.2.0"}}}}

{}

{"cveTags": [], "descriptions": [{"lang": "en", "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nKVM: guest_memfd: Remove bindings on memslot deletion when gmem is dying\n\nWhen unbinding a memslot from a guest_memfd instance, remove the bindings\neven if the guest_memfd file is dying, i.e. even if its file refcount has\ngone to zero. If the memslot is freed before the file is fully released,\nnullifying the memslot side of the binding in kvm_gmem_release() will\nwrite to freed memory, as detected by syzbot+KASAN:\n\n ==================================================================\n BUG: KASAN: slab-use-after-free in kvm_gmem_release+0x176/0x440 virt/kvm/guest_memfd.c:353\n Write of size 8 at addr ffff88807befa508 by task syz.0.17/6022\n\n CPU: 0 UID: 0 PID: 6022 Comm: syz.0.17 Not tainted syzkaller #0 PREEMPT(full)\n Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/02/2025\n Call Trace:\n <TASK>\n dump_stack_lvl+0x189/0x250 lib/dump_stack.c:120\n print_address_description mm/kasan/report.c:378 [inline]\n print_report+0xca/0x240 mm/kasan/report.c:482\n kasan_report+0x118/0x150 mm/kasan/report.c:595\n kvm_gmem_release+0x176/0x440 virt/kvm/guest_memfd.c:353\n __fput+0x44c/0xa70 fs/file_table.c:468\n task_work_run+0x1d4/0x260 kernel/task_work.c:227\n resume_user_mode_work include/linux/resume_user_mode.h:50 [inline]\n exit_to_user_mode_loop+0xe9/0x130 kernel/entry/common.c:43\n exit_to_user_mode_prepare include/linux/irq-entry-common.h:225 [inline]\n syscall_exit_to_user_mode_work include/linux/entry-common.h:175 [inline]\n syscall_exit_to_user_mode include/linux/entry-common.h:210 [inline]\n do_syscall_64+0x2bd/0xfa0 arch/x86/entry/syscall_64.c:100\n entry_SYSCALL_64_after_hwframe+0x77/0x7f\n RIP: 0033:0x7fbeeff8efc9\n </TASK>\n\n Allocated by task 6023:\n kasan_save_stack mm/kasan/common.c:56 [inline]\n kasan_save_track+0x3e/0x80 mm/kasan/common.c:77\n poison_kmalloc_redzone mm/kasan/common.c:397 [inline]\n __kasan_kmalloc+0x93/0xb0 mm/kasan/common.c:414\n kasan_kmalloc include/linux/kasan.h:262 [inline]\n __kmalloc_cache_noprof+0x3e2/0x700 mm/slub.c:5758\n kmalloc_noprof include/linux/slab.h:957 [inline]\n kzalloc_noprof include/linux/slab.h:1094 [inline]\n kvm_set_memory_region+0x747/0xb90 virt/kvm/kvm_main.c:2104\n kvm_vm_ioctl_set_memory_region+0x6f/0xd0 virt/kvm/kvm_main.c:2154\n kvm_vm_ioctl+0x957/0xc60 virt/kvm/kvm_main.c:5201\n vfs_ioctl fs/ioctl.c:51 [inline]\n __do_sys_ioctl fs/ioctl.c:597 [inline]\n __se_sys_ioctl+0xfc/0x170 fs/ioctl.c:583\n do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]\n do_syscall_64+0xfa/0xfa0 arch/x86/entry/syscall_64.c:94\n entry_SYSCALL_64_after_hwframe+0x77/0x7f\n\n Freed by task 6023:\n kasan_save_stack mm/kasan/common.c:56 [inline]\n kasan_save_track+0x3e/0x80 mm/kasan/common.c:77\n kasan_save_free_info+0x46/0x50 mm/kasan/generic.c:584\n poison_slab_object mm/kasan/common.c:252 [inline]\n __kasan_slab_free+0x5c/0x80 mm/kasan/common.c:284\n kasan_slab_free include/linux/kasan.h:234 [inline]\n slab_free_hook mm/slub.c:2533 [inline]\n slab_free mm/slub.c:6622 [inline]\n kfree+0x19a/0x6d0 mm/slub.c:6829\n kvm_set_memory_region+0x9c4/0xb90 virt/kvm/kvm_main.c:2130\n kvm_vm_ioctl_set_memory_region+0x6f/0xd0 virt/kvm/kvm_main.c:2154\n kvm_vm_ioctl+0x957/0xc60 virt/kvm/kvm_main.c:5201\n vfs_ioctl fs/ioctl.c:51 [inline]\n __do_sys_ioctl fs/ioctl.c:597 [inline]\n __se_sys_ioctl+0xfc/0x170 fs/ioctl.c:583\n do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]\n do_syscall_64+0xfa/0xfa0 arch/x86/entry/syscall_64.c:94\n entry_SYSCALL_64_after_hwframe+0x77/0x7f\n\nDeliberately don't acquire filemap invalid lock when the file is dying as\nthe lifecycle of f_mapping is outside the purview of KVM. Dereferencing\nthe mapping is *probably* fine, but there's no need to invalidate anything\nas memslot deletion is responsible for zapping SPTEs, and the only code\nthat can access the dying file is kvm_gmem_release(), whose core code is\nmutual\n---truncated---"}], "id": "CVE-2025-40274", "lastModified": "2025-12-06T22:15:55.163", "metrics": {}, "published": "2025-12-06T22:15:55.163", "references": [{"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "url": "https://git.kernel.org/stable/c/393893693a523e053f84d69320d090b93503f79f"}, {"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "url": "https://git.kernel.org/stable/c/a8ac2bd0f98e1a230f1eb3260fa552bf2ef1753b"}, {"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "url": "https://git.kernel.org/stable/c/ae431059e75d36170a5ae6b44cc4d06d43613215"}], "sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "vulnStatus": "Received"}

{}

{}