CVE-2025-68810
- Source
- https://cve.org/CVERecord?id=CVE-2025-68810
- Import Source
- https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2025-68810.json
- JSON Data
- https://api.osv.dev/v1/vulns/CVE-2025-68810
- Downstream
- Published
- 2026-01-13T15:29:16.475Z
- Modified
- 2026-02-09T19:34:46.292712Z
- Summary
- KVM: Disallow toggling KVM_MEM_GUEST_MEMFD on an existing memslot
- Details
-
In the Linux kernel, the following vulnerability has been resolved:
KVM: Disallow toggling KVMMEMGUEST_MEMFD on an existing memslot
Reject attempts to disable KVMMEMGUESTMEMFD on a memslot that was initially created with a guestmemfd binding, as KVM doesn't support toggling KVMMEMGUESTMEMFD on existing memslots. KVM prevents enabling KVMMEMGUESTMEMFD, but doesn't prevent clearing the flag.
Failure to reject the new memslot results in a use-after-free due to KVM not unbinding from the guestmemfd instance. Unbinding on a FLAGSONLY change is easy enough, and can/will be done as a hardening measure (in anticipation of KVM supporting dirty logging on guest_memfd at some point), but fixing the use-after-free would only address the immediate symptom.
================================================================== BUG: KASAN: slab-use-after-free in kvmgmemrelease+0x362/0x400 [kvm] Write of size 8 at addr ffff8881111ae908 by task repro/745
CPU: 7 UID: 1000 PID: 745 Comm: repro Not tainted 6.18.0-rc6-115d5de2eef3-next-kasan #3 NONE Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 0.0.0 02/06/2015 Call Trace: <TASK> dumpstacklvl+0x51/0x60 printreport+0xcb/0x5c0 kasanreport+0xb4/0xe0 kvmgmemrelease+0x362/0x400 [kvm] _fput+0x2fa/0x9d0 taskworkrun+0x12c/0x200 doexit+0x6ae/0x2100 dogroupexit+0xa8/0x230 _x64sysexitgroup+0x3a/0x50 x64syscall+0x737/0x740 dosyscall64+0x5b/0x900 entrySYSCALL64afterhwframe+0x4b/0x53 RIP: 0033:0x7f581f2eac31 </TASK>
Allocated by task 745 on cpu 6 at 9.746971s: kasansavestack+0x20/0x40 kasansavetrack+0x13/0x50 _kasankmalloc+0x77/0x90 kvmsetmemoryregion.part.0+0x652/0x1110 [kvm] kvmvmioctl+0x14b0/0x3290 [kvm] _x64sysioctl+0x129/0x1a0 dosyscall64+0x5b/0x900 entrySYSCALL64afterhwframe+0x4b/0x53
Freed by task 745 on cpu 6 at 9.747467s: kasansavestack+0x20/0x40 kasansavetrack+0x13/0x50 _kasansavefreeinfo+0x37/0x50 _kasanslabfree+0x3b/0x60 kfree+0xf5/0x440 kvmsetmemslot+0x3c2/0x1160 [kvm] kvmsetmemoryregion.part.0+0x86a/0x1110 [kvm] kvmvmioctl+0x14b0/0x3290 [kvm] _x64sysioctl+0x129/0x1a0 dosyscall64+0x5b/0x900 entrySYSCALL64after_hwframe+0x4b/0x53
- Database specific
{ "cna_assigner": "Linux", "osv_generated_from": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2025/68xxx/CVE-2025-68810.json" }- References
-
- https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git
- https://git.kernel.org/stable/c/89dbbe6ff323fc34659621a577fe0af913f47386
- https://git.kernel.org/stable/c/9935df5333aa503a18de5071f53762b65c783c4c
- https://git.kernel.org/stable/c/cb51bef465d8ec60a968507330e01020e35dc127
- https://github.com/CVEProject/cvelistV5/tree/main/cves/2025/68xxx/CVE-2025-68810.json
- https://nvd.nist.gov/vuln/detail/CVE-2025-68810
Affected packages
Git / git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git
Affected ranges
- Type
- GIT
- Repo
- https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git
- Events
-
Introduceda7800aa80ea4d5356b8474c2302812e9d4926fa6Fixed89dbbe6ff323fc34659621a577fe0af913f47386Fixedcb51bef465d8ec60a968507330e01020e35dc127Fixed9935df5333aa503a18de5071f53762b65c783c4c