{ "schema_version": "1.6.1", "id": "RPI-CVE-2025-68810", "modified": "2026-10-09T11:39:44Z", "upstream": [ "CVE-2025-68810" ], "published": "2026-01-13T15:29:33Z", "summary": "KVM: Disallow toggling KVM_MEM_GUEST_MEMFD on an existing memslot", "details": "In the Linux kernel, the following vulnerability has been resolved:\n\nKVM: Disallow toggling KVM_MEM_GUEST_MEMFD on an existing memslot\n\nReject attempts to disable KVM_MEM_GUEST_MEMFD on a memslot that was\ninitially created with a guest_memfd binding, as KVM doesn't support\ntoggling KVM_MEM_GUEST_MEMFD on existing memslots. KVM prevents enabling\nKVM_MEM_GUEST_MEMFD, but doesn't prevent clearing the flag.\n\nFailure to reject the new memslot results in a use-after-free due to KVM\nnot unbinding from the guest_memfd instance. Unbinding on a FLAGS_ONLY\nchange is easy enough, and can/will be done as a hardening measure (in\nanticipation of KVM supporting dirty logging on guest_memfd at some point),\nbut fixing the use-after-free would only address the immediate symptom.\n\n ==================================================================\n BUG: KASAN: slab-use-after-free in kvm_gmem_release+0x362/0x400 [kvm]\n Write of size 8 at addr ffff8881111ae908 by task repro/745\n\n CPU: 7 UID: 1000 PID: 745 Comm: repro Not tainted 6.18.0-rc6-115d5de2eef3-next-kasan #3 NONE\n Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 0.0.0 02/06/2015\n Call Trace:\n \n dump_stack_lvl+0x51/0x60\n print_report+0xcb/0x5c0\n kasan_report+0xb4/0xe0\n kvm_gmem_release+0x362/0x400 [kvm]\n __fput+0x2fa/0x9d0\n task_work_run+0x12c/0x200\n do_exit+0x6ae/0x2100\n do_group_exit+0xa8/0x230\n __x64_sys_exit_group+0x3a/0x50\n x64_sys_call+0x737/0x740\n do_syscall_64+0x5b/0x900\n entry_SYSCALL_64_after_hwframe+0x4b/0x53\n RIP: 0033:0x7f581f2eac31\n \n\n Allocated by task 745 on cpu 6 at 9.746971s:\n kasan_save_stack+0x20/0x40\n kasan_save_track+0x13/0x50\n __kasan_kmalloc+0x77/0x90\n kvm_set_memory_region.part.0+0x652/0x1110 [kvm]\n kvm_vm_ioctl+0x14b0/0x3290 [kvm]\n __x64_sys_ioctl+0x129/0x1a0\n do_syscall_64+0x5b/0x900\n entry_SYSCALL_64_after_hwframe+0x4b/0x53\n\n Freed by task 745 on cpu 6 at 9.747467s:\n kasan_save_stack+0x20/0x40\n kasan_save_track+0x13/0x50\n __kasan_save_free_info+0x37/0x50\n __kasan_slab_free+0x3b/0x60\n kfree+0xf5/0x440\n kvm_set_memslot+0x3c2/0x1160 [kvm]\n kvm_set_memory_region.part.0+0x86a/0x1110 [kvm]\n kvm_vm_ioctl+0x14b0/0x3290 [kvm]\n __x64_sys_ioctl+0x129/0x1a0\n do_syscall_64+0x5b/0x900\n entry_SYSCALL_64_after_hwframe+0x4b/0x53", "severity": [ { "type": "CVSS_V3", "score": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H" } ], "affected": [ { "package": { "ecosystem": "Raspberry Pi OS:12", "name": "linux" }, "versions": [ "1:6.12.20-1+rpt1~bpo12+1", "1:6.12.25-1+rpt1", "1:6.12.34-1+rpt1~bookworm", "1:6.12.47-1+rpt1~bookworm", "1:6.12.62-1+rpt1~bookworm" ], "ecosystem_specific": { "binaries": [ { "binary_name": "linux-image-6.12.20+rpt-rpi-2712", "binary_version": "1:6.12.20-1+rpt1~bpo12+1" }, { "binary_name": "linux-image-6.12.20+rpt-rpi-v8", "binary_version": "1:6.12.20-1+rpt1~bpo12+1" }, { "binary_name": "linux-image-6.12.25+rpt-rpi-2712", "binary_version": "1:6.12.25-1+rpt1" }, { "binary_name": "linux-image-6.12.25+rpt-rpi-v8", "binary_version": "1:6.12.25-1+rpt1" }, { "binary_name": "linux-image-6.12.34+rpt-rpi-2712", "binary_version": "1:6.12.34-1+rpt1~bookworm" }, { "binary_name": "linux-image-6.12.34+rpt-rpi-v8", "binary_version": "1:6.12.34-1+rpt1~bookworm" }, { "binary_name": "linux-image-6.12.34+rpt-rpi-v8-rt", "binary_version": "1:6.12.34-1+rpt1~bookworm" }, { "binary_name": "linux-image-6.12.47+rpt-rpi-2712", "binary_version": "1:6.12.47-1+rpt1~bookworm" }, { "binary_name": "linux-image-6.12.47+rpt-rpi-v8", "binary_version": "1:6.12.47-1+rpt1~bookworm" }, { "binary_name": "linux-image-6.12.47+rpt-rpi-v8-rt", "binary_version": "1:6.12.47-1+rpt1~bookworm" }, { "binary_name": "linux-image-6.12.62+rpt-rpi-2712", "binary_version": "1:6.12.62-1+rpt1~bookworm" }, { "binary_name": "linux-image-6.12.62+rpt-rpi-v8", "binary_version": "1:6.12.62-1+rpt1~bookworm" }, { "binary_name": "linux-image-6.12.62+rpt-rpi-v8-rt", "binary_version": "1:6.12.62-1+rpt1~bookworm" } ] }, "database_specific": { "per_version": { "1:6.12.20-1+rpt1~bpo12+1": { "linux_commit": "cd231d4775b14f228606c09f219b48308f6ab3aa", "upstream_version": "6.12.20", "assessment": "commit ancestry (strak rule)", "upstream_fixed": "6.12.64" }, "1:6.12.25-1+rpt1": { "linux_commit": "3dd2c2c507c271d411fab2e82a2b3b7e0b6d3f16", "upstream_version": "6.12.25", "assessment": "commit ancestry (strak rule)", "upstream_fixed": "6.12.64" }, "1:6.12.34-1+rpt1~bookworm": { "linux_commit": "8f77e03530f65209a377d25023e912b288e039cd", "upstream_version": "6.12.34", "assessment": "commit ancestry (strak rule)", "upstream_fixed": "6.12.64" }, "1:6.12.47-1+rpt1~bookworm": { "linux_commit": "359f37f0faefb712add32a39f98751aea67d5c1f", "upstream_version": "6.12.47", "assessment": "commit ancestry (strak rule)", "upstream_fixed": "6.12.64" }, "1:6.12.62-1+rpt1~bookworm": { "linux_commit": "a1073743767f9e7fdc7017ababd2a07ea0c97c1c", "upstream_version": "6.12.62", "assessment": "commit ancestry (strak rule)", "upstream_fixed": "6.12.64" } } } }, { "package": { "ecosystem": "Raspberry Pi OS:13", "name": "linux" }, "versions": [ "1:6.12.19-1+rpt1~bpo12+1", "1:6.12.19-1+rpt1", "1:6.12.20-1+rpt1", "1:6.12.25-1+rpt1+trixie", "1:6.12.34-1+rpt1", "1:6.12.47-1+rpt1", "1:6.12.62-1+rpt1" ], "ecosystem_specific": { "binaries": [ { "binary_name": "linux-image-6.12.19+rpt-rpi-2712", "binary_version": "1:6.12.19-1+rpt1~bpo12+1" }, { "binary_name": "linux-image-6.12.19+rpt-rpi-v8", "binary_version": "1:6.12.19-1+rpt1~bpo12+1" }, { "binary_name": "linux-image-6.12.19+rpt-rpi-2712", "binary_version": "1:6.12.19-1+rpt1" }, { "binary_name": "linux-image-6.12.19+rpt-rpi-v8", "binary_version": "1:6.12.19-1+rpt1" }, { "binary_name": "linux-image-6.12.20+rpt-rpi-2712", "binary_version": "1:6.12.20-1+rpt1" }, { "binary_name": "linux-image-6.12.20+rpt-rpi-v8", "binary_version": "1:6.12.20-1+rpt1" }, { "binary_name": "linux-image-6.12.25+rpt-rpi-2712", "binary_version": "1:6.12.25-1+rpt1+trixie" }, { "binary_name": "linux-image-6.12.25+rpt-rpi-v8", "binary_version": "1:6.12.25-1+rpt1+trixie" }, { "binary_name": "linux-image-6.12.25+rpt-rpi-v8-rt", "binary_version": "1:6.12.25-1+rpt1+trixie" }, { "binary_name": "linux-image-6.12.34+rpt-rpi-2712", "binary_version": "1:6.12.34-1+rpt1" }, { "binary_name": "linux-image-6.12.34+rpt-rpi-v8", "binary_version": "1:6.12.34-1+rpt1" }, { "binary_name": "linux-image-6.12.34+rpt-rpi-v8-rt", "binary_version": "1:6.12.34-1+rpt1" }, { "binary_name": "linux-image-6.12.47+rpt-rpi-2712", "binary_version": "1:6.12.47-1+rpt1" }, { "binary_name": "linux-image-6.12.47+rpt-rpi-v8", "binary_version": "1:6.12.47-1+rpt1" }, { "binary_name": "linux-image-6.12.47+rpt-rpi-v8-rt", "binary_version": "1:6.12.47-1+rpt1" }, { "binary_name": "linux-image-6.12.62+rpt-rpi-2712", "binary_version": "1:6.12.62-1+rpt1" }, { "binary_name": "linux-image-6.12.62+rpt-rpi-v8", "binary_version": "1:6.12.62-1+rpt1" }, { "binary_name": "linux-image-6.12.62+rpt-rpi-v8-rt", "binary_version": "1:6.12.62-1+rpt1" } ] }, "database_specific": { "per_version": { "1:6.12.19-1+rpt1~bpo12+1": { "linux_commit": "121c2c384b9c2f4790ffb31b2cd25c7d75c8fda0", "upstream_version": "6.12.19", "assessment": "commit ancestry (strak rule)", "upstream_fixed": "6.12.64" }, "1:6.12.19-1+rpt1": { "linux_commit": "121c2c384b9c2f4790ffb31b2cd25c7d75c8fda0", "upstream_version": "6.12.19", "assessment": "commit ancestry (strak rule)", "upstream_fixed": "6.12.64" }, "1:6.12.20-1+rpt1": { "linux_commit": "cd231d4775b14f228606c09f219b48308f6ab3aa", "upstream_version": "6.12.20", "assessment": "commit ancestry (strak rule)", "upstream_fixed": "6.12.64" }, "1:6.12.25-1+rpt1+trixie": { "linux_commit": "3dd2c2c507c271d411fab2e82a2b3b7e0b6d3f16", "upstream_version": "6.12.25", "assessment": "commit ancestry (strak rule)", "upstream_fixed": "6.12.64" }, "1:6.12.34-1+rpt1": { "linux_commit": "8f77e03530f65209a377d25023e912b288e039cd", "upstream_version": "6.12.34", "assessment": "commit ancestry (strak rule)", "upstream_fixed": "6.12.64" }, "1:6.12.47-1+rpt1": { "linux_commit": "359f37f0faefb712add32a39f98751aea67d5c1f", "upstream_version": "6.12.47", "assessment": "commit ancestry (strak rule)", "upstream_fixed": "6.12.64" }, "1:6.12.62-1+rpt1": { "linux_commit": "a1073743767f9e7fdc7017ababd2a07ea0c97c1c", "upstream_version": "6.12.62", "assessment": "commit ancestry (strak rule)", "upstream_fixed": "6.12.64" } } } } ], "references": [ { "type": "ADVISORY", "url": "https://www.cve.org/CVERecord?id=CVE-2025-68810" }, { "type": "FIX", "url": "https://git.kernel.org/stable/c/89dbbe6ff323fc34659621a577fe0af913f47386" }, { "type": "FIX", "url": "https://git.kernel.org/stable/c/cb51bef465d8ec60a968507330e01020e35dc127" }, { "type": "FIX", "url": "https://git.kernel.org/stable/c/9935df5333aa503a18de5071f53762b65c783c4c" } ], "database_specific": { "source": "https://git.kernel.org/pub/scm/linux/security/vulns.git", "upstream_modified": "2026-08-05T12:19:11Z", "severity": { "source": "kernel CNA", "cvss_v3_score": 7.8, "cvss_v3_severity": "High", "scenario": "AV:L - Exploitation requires local ioctl operations on a KVM VM file descriptor followed by closing the guest_memfd; no guest or network path reaches the flaw.\nAC:L - The attacker deterministically creates and binds a guest_memfd slot, clears its flag, reclaims the freed allocation, and closes the file. No race or condition outside the attacker\u2019s control is required.\nPR:L - The attacker needs access to /dev/kvm and an attacker-owned VM descriptor, typically granted through the kvm group or a device ACL. None of the relevant ioctls requires a capability or init-namespace root.\nUI:N - The attacker performs the complete ioctl and file-release sequence without any victim action.\nS:U - The vulnerable interface is invoked by host userspace rather than a guest, and the resulting host-kernel compromise remains within the host OS security authority.\nC:H - The reclaimable stale memslot is subsequently read during MMU invalidation, including attacker-influenceable bounds and architecture pointers. Exploiting this kernel UAF can expose arbitrary host kernel or VM memory.\nI:H - Release performs an attacker-timed eight-byte NULL write into a reclaimed allocation and subsequently follows stale MMU metadata. Heap shaping can turn this into arbitrary kernel-state corruption or host code execution.\nA:H - The flaw demonstrably causes a slab use-after-free write, and the x86 path can also issue a warning before release. Repeated triggering can corrupt MMU state, oops, or panic the host kernel." } } }