PT-2024-11263 · Linux+1 · Linux Kernel+1

Published 2021-06-15 · Updated 2024-05-21 · CVE-2021-47256

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 prior to 4.19.95

Description A vulnerability in the Linux kernel has been resolved, which was triggered by a call to munlock pagevec to clear page LRU without lock page. This resulted in a kernel panic due to a BUG ON condition in clear inode. The issue occurred because memory failure called identify page state without waiting for page writeback, and after truncate error page cleared the mapping of the page, end page writeback did not call sb clear inode writeback to clear inode->i wb list. The fix involves checking PageWriteback to determine whether to skip wait on page writeback.

Recommendations To resolve this issue, update the Linux kernel to a version later than 4.19.95. As a temporary workaround, consider disabling the munlock pagevec function until a patch is available.

Fix

Weakness Enumeration

CWE-567

Related Identifiers

BDU:2025-14612

CVE-2021-47256

Affected Products

Astra Linux

Linux Kernel

References · 24

• https://bdu.fstec.ru/vul/2025-14612 · Security Note
• https://security-tracker.debian.org/tracker/CVE-2021-47256 · Vendor Advisory
• https://git.kernel.org/stable/c/d05267fd27a5c4f54e06daefa3035995d765ca0c · Patch
• https://git.kernel.org/stable/c/566345aaabac853aa866f53a219c4b02a6beb527 · Patch
• https://git.kernel.org/stable/c/9e379da727a7a031be9b877cde7b9c34a0fb8306 · Patch
• https://git.kernel.org/stable/c/28788dc5c70597395b6b451dae4549bbaa8e2c56 · Patch
• https://cve.org/CVERecord?id=CVE-2021-47256 · Security Note
• https://git.kernel.org/stable/c/e8675d291ac007e1c636870db880f837a9ea112a · Patch
• https://osv.dev/vulnerability/UBUNTU-CVE-2021-47256 · Vendor Advisory
• https://git.kernel.org/stable/c/6d210d547adc2218ef8b5bcf23518c5f2f1fd872 · Patch
• https://osv.dev/vulnerability/CVE-2021-47256 · Vendor Advisory
• https://nvd.nist.gov/vuln/detail/CVE-2021-47256 · Security Note
• https://osv.dev/vulnerability/DEBIAN-CVE-2021-47256 · Vendor Advisory
• https://ubuntu.com/security/CVE-2021-47256 · Vendor Advisory
• https://git.linuxtesting.ru/pub/scm/linux/kernel/git/lvc/linux-stable.git/commit/?h=v5.10.176-lvc1&id=9e379da727a7a031be9b877cde7b9c34a0fb8306 · Note