PT-2025-11013 · Linux+7 · Linux Kernel+7

Colm Harrington

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Published

2025-02-05

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Updated

2025-11-12

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CVE-2025-21851

CVSS v3.1

3.3

Low

VectorAV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:L
Name of the Vulnerable Software and Affected Versions: Linux kernel (affected versions not specified)
Description: A softlockup issue in the Linux kernel has been identified, specifically in the bpf (Berkeley Packet Filter) component. This issue occurs on aarch64 kernels with a page size of 64KB, where arena htab tests cause a segmentation fault and soft lockup. The problem arises when arena map free() calls apply to existing page range() with an unaligned address, leading to a soft lockup. The issue is not observed with 4k pages on aarch64.
Recommendations: As a temporary workaround, consider disabling the arena map free() function until a patch is available. To fix the issue, round up GUARD SZ to PAGE SIZE << 1 so that the division by 2 in bpf arena get kern vm start() returns a page-aligned value. At the moment, there is no information about a newer version that contains a fix for this vulnerability.

Exploit

Improper Locking

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Weakness Enumeration

Related Identifiers

ALSA-2025:20095
ALSA-2025:20518
ALT-PU-2025-4807
BDU:2025-12262
CVE-2025-21851
INFSA-2025_20518
RHSA-2025:20095
RHSA-2025:20518
RHSA-2025_20518
USN-7521-1
USN-7521-2
USN-7521-3

Affected Products

Alt Linux
Almalinux
Astra Linux
Linuxmint
Linux Kernel
Red Hat
Rocky Linux
Ubuntu