PT-2024-11337 · Linux+6 · Linux Kernel+6

Zhen Lei

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Published

2021-07-13

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Updated

2024-12-24

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CVE-2021-47338

CVSS v3.1

7.8

High

VectorAV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
Name of the Vulnerable Software and Affected Versions Linux kernel versions prior to 5.10.45-rc1+
Description The issue is related to the execution of fb delete videomode() not being based on the result of the previous fbcon mode deleted(), leading to the direct deletion of a mode regardless of whether it is still in use. This may cause a use-after-free (UAF) vulnerability. The vulnerability is identified in the fb mode is equal() function in drivers/video/fbdev/core/modedb.c.
Recommendations To resolve the issue, update the Linux kernel to a version that includes the fix for this vulnerability. As a temporary workaround, consider disabling the fb delete videomode() function until a patch is available. Restrict access to the vulnerable module drivers/video/fbdev/core/modedb.c to minimize the risk of exploitation. Avoid using the fb set var() function in the affected API endpoint until the issue is resolved. At the moment, there is no information about a newer version that contains a fix for this vulnerability.

Use After Free

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Weakness Enumeration

Related Identifiers

ALSA-2024:7000
ALSA-2024:7001
BDU:2025-07329
CESA-2024_7000
CESA-2024_7001
CVE-2021-47338
INFSA-2024_7000
INFSA-2024_7001
OPENSUSE-SU-2024_2185-1
RHSA-2024:7000
RHSA-2024:7001
RHSA-2024_7000
RHSA-2024_7001
RLSA-2024:7001
SUSE-SU-2024:2010-1
SUSE-SU-2024:2183-1
SUSE-SU-2024:2185-1

Affected Products

Almalinux
Astra Linux
Centos
Linux Kernel
Red Hat
Rocky Linux
Suse