PT-2021-8271 · Linux+2 · Linux Kernel+2

He Ying · Published 2021-04-23 · Updated 2024-12-11 · CVE-2021-46961

Positive Technologies (AI Summary)

CVSS v3.1

5.5

Medium

Base vector

AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H

Name of the Vulnerable Software and Affected Versions Linux kernel versions 4.19.95.aarch64 and earlier

Description The vulnerability is related to the handling of spurious interrupts in the Linux kernel. When a spurious interrupt occurs, the kernel should not enable interrupts, but in this case, it does, leading to a nested NMI situation. This can cause a kernel panic and potentially allow an attacker to crash the system. The issue is caused by a 'BUG ON(in nmi())' in nmi enter(). Moving the handling of spurious interrupts as early as possible in the GICv3 handler fixes this issue.

Recommendations To resolve this issue, update the Linux kernel to a version that includes the fix for this vulnerability. Specifically, for Linux kernel version 4.19.95.aarch64, update to a newer version that includes the patch for irqchip/gic-v3: Do not enable irqs when handling spurious interrupts. As a temporary workaround, consider disabling the nmi enter() function until a patch is available. However, this is not a recommended long-term solution, as it may have unintended consequences on system stability and performance.

Fix

RCE

Weakness Enumeration

CWE-20

Related Identifiers

BDU:2025-00821

CVE-2021-46961

OPENSUSE-SU-2024_1489-1

SUSE-SU-2024:1454-1

SUSE-SU-2024:1465-1

SUSE-SU-2024:1489-1

Affected Products

Astra Linux

Linux Kernel

Suse

References · 346

• https://osv.dev/vulnerability/SUSE-SU-2024:1489-1 · Vendor Advisory
• https://osv.dev/vulnerability/CVE-2021-46961 · Vendor Advisory
• https://bdu.fstec.ru/vul/2025-00821 · Security Note
• https://git.kernel.org/stable/c/e7ea8e46e3b777be26aa855fe07778c415f24926 · Patch
• https://wiki.astralinux.ru/astra-linux-se81-bulletin-20241206SE81 · Vendor Advisory
• https://security-tracker.debian.org/tracker/CVE-2021-46961 · Vendor Advisory
• https://osv.dev/vulnerability/UBUNTU-CVE-2021-46961 · Vendor Advisory
• https://nvd.nist.gov/vuln/detail/CVE-2021-46961 · Security Note
• https://git.kernel.org/stable/c/3f72d3709f53af72835af7dc8b15ba61611a0e36 · Patch
• https://cve.org/CVERecord?id=CVE-2021-46961 · Security Note
• https://osv.dev/vulnerability/SUSE-SU-2024:1465-1 · Vendor Advisory
• https://git.kernel.org/stable/c/7be4db5c2b59fa77071c93ca4329876fb9777202 · Patch
• https://ubuntu.com/security/CVE-2021-46961 · Vendor Advisory
• https://osv.dev/vulnerability/DEBIAN-CVE-2021-46961 · Vendor Advisory
• https://git.kernel.org/stable/c/ea817ac1014c04f47885532b55f5d0898deadfba · Patch