#VU105468 Infinite loop in Linux kernel - CVE-2025-21839

Vulnerability identifier: #VU105468

Vulnerability risk: Low

CVSSv4.0: 4.3 [CVSS:4.0/AV:L/AC:L/AT:N/PR:L/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N/E:U/U:Clear]

CVE-ID: CVE-2025-21839

CWE-ID: CWE-835

Exploitation vector: Local

Exploit availability: No

Vulnerable software:
Linux kernel
Operating systems & Components / Operating system

Vendor: Linux Foundation

Description

The vulnerability allows a local user to perform a denial of service (DoS) attack.

The vulnerability exists due to infinite loop within the vcpu_enter_guest() function in arch/x86/kvm/x86.c, within the vmx_sync_dirty_debug_regs() and vmx_vcpu_run() functions in arch/x86/kvm/vmx/vmx.c, within the new_asid() and svm_vcpu_run() functions in arch/x86/kvm/svm/svm.c. A local user can perform a denial of service (DoS) attack.

Mitigation
Install update from vendor's website.

Vulnerable software versions

Linux kernel: 6.13, 6.13.1, 6.13.2, 6.13.3

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External links
https://git.kernel.org/stable/c/4eb063de686bfcdfd03a8c801d1bbe87d2d5eb55
https://git.kernel.org/stable/c/c2fee09fc167c74a64adb08656cb993ea475197e
https://git.kernel.org/stable/c/d456de38d9eb753a4e9fde053c18d4ef8e485339
https://mirrors.edge.kernel.org/pub/linux/kernel/v6.x/ChangeLog-6.13.4

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Q & A

Can this vulnerability be exploited remotely?

No. This vulnerability can be exploited locally. The attacker should have authentication credentials and successfully authenticate on the system.

Is there known malware, which exploits this vulnerability?

No. We are not aware of malware exploiting this vulnerability.