Use-after-free in Linux kernel - CVE-2021-47639
Published: February 26, 2025 / Updated: May 11, 2025
Vulnerability identifier: #VU104501
CSH Severity: Low
CVSS v4.0: CVSS:4.0/AV:L/AC:L/AT:N/PR:L/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N/E:U/U:Clear
CVE-ID: CVE-2021-47639
CWE-ID: CWE-416
Exploitation vector: Local access
Exploit availability:
No public exploit available
Vendor: Linux Foundation
Affected software:
Linux kernel
Linux kernel
Detailed vulnerability description
The vulnerability allows a local user to escalate privileges on the system.
The vulnerability exists due to a use-after-free error within the kvm_tdp_mmu_put_root(), tdp_mmu_next_root(), kvm_tdp_mmu_wrprot_slot(), kvm_tdp_mmu_clear_dirty_slot() and kvm_tdp_mmu_zap_collapsible_sptes() functions in arch/x86/kvm/mmu/tdp_mmu.c. A local user can escalate privileges on the system.
How to mitigate CVE-2021-47639
Install update from vendor's website.
Sources
- https://git.kernel.org/stable/c/0c8a8da182d4333d9bbb9131d765145568c847b2
- https://git.kernel.org/stable/c/8cf6f98ab1d16d5e607635a0c21c4231eb15367e
- https://git.kernel.org/stable/c/af47248407c0c5ae52a752af1ab5ce5b0db91502
- https://git.kernel.org/stable/c/d62007edf01f5c11f75d0f4b1e538fc52a5b1982
- https://mirrors.edge.kernel.org/pub/linux/kernel/v5.x/ChangeLog-5.15.33
- https://mirrors.edge.kernel.org/pub/linux/kernel/v5.x/ChangeLog-5.16.19
- https://mirrors.edge.kernel.org/pub/linux/kernel/v5.x/ChangeLog-5.17.2
- https://mirrors.edge.kernel.org/pub/linux/kernel/v5.x/ChangeLog-5.18