How severe is CVE-2021-4149?

CVE-2021-4149 has a CVSS 3.x base score of 5.5, rated medium severity. It is exploitable over local access with low attack complexity, requires low privileges and no user interaction. Impact on confidentiality is none, integrity none, and availability high.

Is CVE-2021-4149 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (32nd percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2021-4149?

CVE-2021-4149 primarily affects Linux Linux Kernel. In total, 8 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.

How do I fix CVE-2021-4149?

Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround.

When was CVE-2021-4149 published?

CVE-2021-4149 was published on 2022-03-23 and last updated on 2026-06-17.

CVE-2021-4149

CVE-2021-4149 is a medium-severity vulnerability in Linux Linux Kernel with a CVSS 3.x base score of 5.5. It is not currently listed as actively exploited by CISA, and its EPSS exploit-prediction score is low. The underlying weakness is classified as CWE-667.

Key facts

Severity: Medium (CVSS 3.x base score 5.5)
CVSS v2: 2.1
EPSS exploit prediction: 0% (32nd percentile)
Actively exploited: Not listed in CISA KEV
Weakness: CWE-667
Affected product: Linux Linux Kernel
Published: 2022-03-23
Last modified: 2026-06-17

Description

A vulnerability was found in btrfs_alloc_tree_b in fs/btrfs/extent-tree.c in the Linux kernel due to an improper lock operation in btrfs. In this flaw, a user with a local privilege may cause a denial of service (DOS) due to a deadlock problem.

Frequently asked questions

What is CVE-2021-4149?: A vulnerability was found in btrfs_alloc_tree_b in fs/btrfs/extent-tree.c in the Linux kernel due to an improper lock operation in btrfs. In this flaw, a user with a local privilege may cause a denial of service (DOS) due to a deadlock problem.
How severe is CVE-2021-4149?: CVE-2021-4149 has a CVSS 3.x base score of 5.5, rated medium severity. It is exploitable over local access with low attack complexity, requires low privileges and no user interaction. Impact on confidentiality is none, integrity none, and availability high.
Is CVE-2021-4149 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (32nd percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2021-4149?: CVE-2021-4149 primarily affects Linux Linux Kernel. In total, 8 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.
How do I fix CVE-2021-4149?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround.
When was CVE-2021-4149 published?: CVE-2021-4149 was published on 2022-03-23 and last updated on 2026-06-17.

References

Affected products (8)

cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*
cpe:2.3:o:linux:linux_kernel:5.15:-:*:*:*:*:*:*
cpe:2.3:o:linux:linux_kernel:5.15:rc1:*:*:*:*:*:*
cpe:2.3:o:linux:linux_kernel:5.15:rc2:*:*:*:*:*:*
cpe:2.3:o:linux:linux_kernel:5.15:rc3:*:*:*:*:*:*
cpe:2.3:o:linux:linux_kernel:5.15:rc4:*:*:*:*:*:*
cpe:2.3:o:linux:linux_kernel:5.15:rc5:*:*:*:*:*:*
cpe:2.3:o:debian:debian_linux:9.0:*:*:*:*:*:*:*

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