CVE-2023-53756
KVM: VMX: Fix crash due to uninitialized current_vmcs
- Published
- Updated
- Reserved
- Assigned by
- Linux
Description
In the Linux kernel, the following vulnerability has been resolved: KVM: VMX: Fix crash due to uninitialized current_vmcs KVM enables 'Enlightened VMCS' and 'Enlightened MSR Bitmap' when running as a nested hypervisor on top of Hyper-V. When MSR bitmap is updated, evmcs_touch_msr_bitmap function uses current_vmcs per-cpu variable to mark that the msr bitmap was changed. vmx_vcpu_create() modifies the msr bitmap via vmx_disable_intercept_for_msr -> vmx_msr_bitmap_l01_changed which in the end calls this function. The function checks for current_vmcs if it is null but the check is insufficient because current_vmcs is not initialized. Because of this, the code might incorrectly write to the structure pointed by current_vmcs value left by another task. Preemption is not disabled, the current task can be preempted and moved to another CPU while current_vmcs is accessed multiple times from evmcs_touch_msr_bitmap() which leads to crash. The manipulation of MSR bitmaps by callers happens only for vmcs01 so the solution is to use vmx->vmcs01.vmcs instead of current_vmcs. BUG: kernel NULL pointer dereference, address: 0000000000000338 PGD 4e1775067 P4D 0 Oops: 0002 [#1] PREEMPT SMP NOPTI ... RIP: 0010:vmx_msr_bitmap_l01_changed+0x39/0x50 [kvm_intel] ... Call Trace: vmx_disable_intercept_for_msr+0x36/0x260 [kvm_intel] vmx_vcpu_create+0xe6/0x540 [kvm_intel] kvm_arch_vcpu_create+0x1d1/0x2e0 [kvm] kvm_vm_ioctl_create_vcpu+0x178/0x430 [kvm] kvm_vm_ioctl+0x53f/0x790 [kvm] __x64_sys_ioctl+0x8a/0xc0 do_syscall_64+0x5c/0x90 entry_SYSCALL_64_after_hwframe+0x63/0xcd
Timeline
ID reserved
By Linux
Published
- 5 months later
· 5 months later
Record updated
Changes after publication (a new score, a public exploit, EPSS crossing 1, 10 or 50 %, leaving KEV) are kept since November 2026; earlier ones are not known.
Scores
No CVSS score yet: neither the CNA, CISA nor NVD has scored this CVE. NVD status: Deferred.
- EPSS (exploitation in 30 days)
- 0.19% · top 91% of all CVEs (7 Nov 2026)
The list uses the assigner's score when there is one, then CISA's, then NVD's: Not scored.
Affected products
- affected ceef7d10dfb6284d512c499292e6daa35ea83f90 – < 6baebcecf09acd19e2bab1c2911dcdba5d48a1dc
- affected ceef7d10dfb6284d512c499292e6daa35ea83f90 – < 6e7bc50f97c9855da83f1478f722590defd45ff2
- affected ceef7d10dfb6284d512c499292e6daa35ea83f90 – < b2de2b4d4e007f9add46ea8dc06f781835e3ea9f
- affected ceef7d10dfb6284d512c499292e6daa35ea83f90 – < 3ba95cc671c025d0d2a1c7d5e2930f0ff0980cf4
- affected ceef7d10dfb6284d512c499292e6daa35ea83f90 – < 93827a0a36396f2fd6368a54a020f420c8916e9b
- affected 4.18
- unaffected < 4.18
- unaffected 5.10.175 – ≤ 5.10.*
- unaffected 5.15.103 – ≤ 5.15.*
- unaffected 6.1.16 – ≤ 6.1.*
- unaffected 6.2.3 – ≤ 6.2.*
- unaffected 6.3 – ≤ *
References (5)
- https://git.kernel.org/stable/c/6baebcecf09acd19e2bab1c2911dcdba5d48a1dc (opens in a new tab)
- https://git.kernel.org/stable/c/6e7bc50f97c9855da83f1478f722590defd45ff2 (opens in a new tab)
- https://git.kernel.org/stable/c/b2de2b4d4e007f9add46ea8dc06f781835e3ea9f (opens in a new tab)
- https://git.kernel.org/stable/c/3ba95cc671c025d0d2a1c7d5e2930f0ff0980cf4 (opens in a new tab)
- https://git.kernel.org/stable/c/93827a0a36396f2fd6368a54a020f420c8916e9b (opens in a new tab)
Sources
The same CVE in the primary databases and aggregators, to check against.
- CVE.org record (opens in a new tab)
- CVE List JSON (GitHub) (opens in a new tab)
- NVD (opens in a new tab)
- FIRST EPSS (opens in a new tab)
- OSV.dev (opens in a new tab)
- GitHub Advisories (opens in a new tab)
- CIRCL Vulnerability-Lookup (opens in a new tab)
Badge for a README or a ticket
[](https://trackcve.app/cve/CVE-2023-53756)Record last updated .