CVE-2021-47254

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() 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.

Package Linux Kernel
Published 2024-05-21
Last modified 2026-03-17
CVSS version 3.1
Patch available
Yes

CVSS 3.1 score

7.8

out of 10
High
Attack Vector
Local
Attack Complexity
Low
Privileges Required
Low
User Interaction
None
Scope
Unchanged
Confidentiality
High
Integrity
High
Availability
High
Vector string
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H

Weakness type

CWE-416

CVE-2021-47254 is a Use After Free vulnerability

What is Use After Free?

The product references memory after it has been freed, which may cause it to crash, use unexpected values, or execute code. Learn more on MITRE CWE

Affected versions

Linux kernel versions 4.4.181, 4.9.180, 4.14.123, 4.19.47, 5.0.20, 5.1.6, 5.2 and later are affected. Fixed in 4.4.274, 4.9.274, 4.14.238, 4.19.196, 5.4.127, 5.10.45, 5.12.12, 5.13 and their respective stable series.

Affected from
≥ 4.4.181 ≥ 4.9.180 ≥ 4.14.123 ≥ 4.19.47 ≥ 5.0.20 ≥ 5.1.6 ≥ 5.2
Fixed in
✓ 4.4.274 4.4.x ✓ 4.9.274 4.9.x ✓ 4.14.238 4.14.x ✓ 4.19.196 4.19.x ✓ 5.4.127 5.4.x ✓ 5.10.45 5.10.x ✓ 5.12.12 5.12.x ✓ 5.13

References

8 total
Showing 5 of 8 references View all on NVD

Frequently asked questions

  • What is CVE-2021-47254?

    CVE-2021-47254 is a High severity Linux kernel vulnerability with a CVSS score of 7.8 out of 10 , classified as an Use After Free flaw (CWE-416) . It affects Linux kernel versions from 4.4.181 onward and has been patched in 4.4.274, 4.9.274, 4.14.238 and others. CVE-2021-47254 has not been confirmed as actively exploited and is not listed in the CISA KEV catalog.

  • What is the CVSS score for CVE-2021-47254?

    CVE-2021-47254 has a CVSS score of 7.8 out of 10, rated High severity (CVSS 3.1). The vector string is CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H .

  • Is there a patch available for CVE-2021-47254?

    Yes. CVE-2021-47254 has been patched. Fixed versions include 4.4.274, 4.9.274, 4.14.238 and others. If you are running Linux kernel 4.4.181 or later up to the fix versions, apply the relevant patch for your kernel branch.

  • Is CVE-2021-47254 actively exploited?

    No. CVE-2021-47254 has not been confirmed as actively exploited. It is not listed in the CISA Known Exploited Vulnerabilities (KEV) catalog.

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