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CVE-2021-47342

7.8 · HIGH

In the Linux kernel, the following vulnerability has been resolved: ext4: fix possible UAF when remounting r/o a mmp-protected file system After commit 618f003199c6 ("ext4: fix memory leak in ext…

Published May 21, 2024CWE-416EPSS 0.24%

Overview

CVE-2021-47342 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:

ext4: fix possible UAF when remounting r/o a mmp-protected file system

After commit 618f003199c6 ("ext4: fix memory leak in

ext4_fill_super"), after the file system is remounted read-only, there

is a race where the kmmpd thread can exit, causing sbi->s_mmp_tsk to

point at freed memory, which the call to ext4_stop_mmpd() can trip

over.

Fix this by only allowing kmmpd() to exit when it is stopped via

ext4_stop_mmpd().

Bug-Report-Link: <[email protected]>

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/61bb4a1c417e5b95d9edb4f887f131de32e419cbRefgit.kernel.org/stable/c/7ed572cdf11081f8f9e07abd4bea56a3f2c4edbdRefgit.kernel.org/stable/c/b663890d854403e566169f7e90aed5cd6ff64f6bRefgit.kernel.org/stable/c/61bb4a1c417e5b95d9edb4f887f131de32e419cbRefgit.kernel.org/stable/c/7ed572cdf11081f8f9e07abd4bea56a3f2c4edbdRefgit.kernel.org/stable/c/b663890d854403e566169f7e90aed5cd6ff64f6b

How CyberStrike helps

Frequently asked questions

What is CVE-2021-47342?

CVE-2021-47342 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-2021-47342?

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-2021-47342?

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-2021-47342?

CyberStrike is an open-source, AI-augmented pentesting engine. Rather than flag a version number, it tests whether an issue like CVE-2021-47342 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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