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CVE-2021-47338

7.8 · HIGH

In the Linux kernel, the following vulnerability has been resolved: fbmem: Do not delete the mode that is still in use The execution of fb_delete_videomode() is not based on the result of the pre…

Published May 21, 2024CWE-416EPSS 0.27%

Overview

CVE-2021-47338 is a high-severity vulnerability. It was published on May 21, 2024 and has a CVSS 3.1 base score of 7.8 (HIGH).

This vulnerability has a CVSS 3.1 base score of 7.8, rated HIGH. It requires local or adjacent network access to exploit. Some level of privileges is required for exploitation.

Technical description

In the Linux kernel, the following vulnerability has been resolved:

fbmem: Do not delete the mode that is still in use

The execution of fb_delete_videomode() is not based on the result of the

previous fbcon_mode_deleted(). As a result, the mode is directly deleted,

regardless of whether it is still in use, which may cause UAF.

==================================================================

BUG: KASAN: use-after-free in fb_mode_is_equal+0x36e/0x5e0 \

drivers/video/fbdev/core/modedb.c:924

Read of size 4 at addr ffff88807e0ddb1c by task syz-executor.0/18962

CPU: 2 PID: 18962 Comm: syz-executor.0 Not tainted 5.10.45-rc1+ #3

Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS ...

Call Trace:

__dump_stack lib/dump_stack.c:77 [inline]

dump_stack+0x137/0x1be lib/dump_stack.c:118

print_address_description+0x6c/0x640 mm/kasan/report.c:385

__kasan_report mm/kasan/report.c:545 [inline]

kasan_report+0x13d/0x1e0 mm/kasan/report.c:562

fb_mode_is_equal+0x36e/0x5e0 drivers/video/fb

Remediation

Check the references section for vendor advisories, patches, and mitigation guidance. If immediate patching is not possible, review the CVSS vector to understand the attack surface and apply compensating controls such as network segmentation or access restrictions.

References

Refgit.kernel.org/stable/c/087bff9acd2ec6db3f61aceb3224bde90fe0f7f8Refgit.kernel.org/stable/c/0af778269a522c988ef0b4188556aba97fb420ccRefgit.kernel.org/stable/c/359311b85ebec7c07c3a08ae2f3def946cad33faRefgit.kernel.org/stable/c/d6e76469157d8f240e5dec6f8411aa8d306b1126Refgit.kernel.org/stable/c/f193509afc7ff37a46862610c93b896044d5b693Refgit.kernel.org/stable/c/087bff9acd2ec6db3f61aceb3224bde90fe0f7f8Refgit.kernel.org/stable/c/0af778269a522c988ef0b4188556aba97fb420ccRefgit.kernel.org/stable/c/359311b85ebec7c07c3a08ae2f3def946cad33faRefgit.kernel.org/stable/c/d6e76469157d8f240e5dec6f8411aa8d306b1126Refgit.kernel.org/stable/c/f193509afc7ff37a46862610c93b896044d5b693

How CyberStrike helps

Frequently asked questions

What is CVE-2021-47338?

CVE-2021-47338 is a high-severity vulnerability. It was published on May 21, 2024 and has a CVSS 3.1 base score of 7.8 (HIGH).

How severe is CVE-2021-47338?

This vulnerability has a CVSS 3.1 base score of 7.8, rated HIGH. It requires local or adjacent network access to exploit. Some level of privileges is required for exploitation.

How do I fix or remediate CVE-2021-47338?

Check the references section for vendor advisories, patches, and mitigation guidance. If immediate patching is not possible, review the CVSS vector to understand the attack surface and apply compensating controls such as network segmentation or access restrictions.

How can CyberStrike help with CVE-2021-47338?

CyberStrike is an open-source, AI-augmented pentesting engine. Rather than flag a version number, it tests whether an issue like CVE-2021-47338 is actually reachable in your own applications and APIs, then verifies each finding before reporting it. That tells you if the weakness is a real, exploitable risk in your environment or a false positive you can safely deprioritize.

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