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CVE-2021-47254

7.8 · HIGH

In the Linux kernel, the following vulnerability has been resolved: gfs2: Fix use-after-free in gfs2_glock_shrink_scan The GLF_LRU flag is checked under lru_lock in gfs2_glock_remove_from_lru() t…

Published May 21, 2024CWE-416EPSS 0.24%

Overview

CVE-2021-47254 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:

gfs2: Fix use-after-free in gfs2_glock_shrink_scan

The GLF_LRU flag is checked under lru_lock in gfs2_glock_remove_from_lru() to

remove the glock from the lru list in __gfs2_glock_put().

On the shrink scan path, the same flag is cleared under lru_lock but because

of cond_resched_lock(&lru_lock) in gfs2_dispose_glock_lru(), progress on the

put side can be made without deleting the glock from the lru list.

Keep GLF_LRU across the race window opened by cond_resched_lock(&lru_lock) to

ensure correct behavior on both sides - clear GLF_LRU after list_del under

lru_lock.

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/0364742decb0f02bc183404868b82896f7992595Refgit.kernel.org/stable/c/094bf5670e762afa243d2c41a5c4ab71c7447bf4Refgit.kernel.org/stable/c/1ab19c5de4c537ec0d9b21020395a5b5a6c059b2Refgit.kernel.org/stable/c/38ce329534500bf4ae71f81df6a37a406cf187b4Refgit.kernel.org/stable/c/86fd5b27db743a0ce0cc245e3a34813b2aa6ec1dRefgit.kernel.org/stable/c/92869945cc5b78ee8a1ef90336fe070893e3458aRefgit.kernel.org/stable/c/a61156314b66456ab6a291ed5deba1ebd002ab3cRefgit.kernel.org/stable/c/e87ef30fe73e7e10d2c85bdcc778dcec24dca553Refgit.kernel.org/stable/c/0364742decb0f02bc183404868b82896f7992595Refgit.kernel.org/stable/c/094bf5670e762afa243d2c41a5c4ab71c7447bf4

How CyberStrike helps

Frequently asked questions

What is CVE-2021-47254?

CVE-2021-47254 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-2021-47254?

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-2021-47254?

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-2021-47254?

CyberStrike is an open-source, AI-augmented pentesting engine. Rather than flag a version number, it tests whether an issue like CVE-2021-47254 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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