CVE-2021-4155

Name: CVE-2021-4155
Creator: NVD / NIST
Published: 2022-08-24T16:15:09.607+00:00
License: https://creativecommons.org/publicdomain/zero/1.0/

MEDIUMCVSS 5.5/10EPSS 0.29%

Last modified Jun 17, 2026

CVE-2021-4155 is a medium-severity vulnerability rated 5.5/10 on the CVSS scale. A data leak flaw was found in the way XFS_IOC_ALLOCSP IOCTL in the XFS filesystem allowed for size increase of files with unaligned size. A local attacker could use this flaw to leak data on the XFS filesystem otherwise not accessible to them.. EPSS estimates a 0.29% chance of exploitation in the next 30 days.

Description

A data leak flaw was found in the way XFS_IOC_ALLOCSP IOCTL in the XFS filesystem allowed for size increase of files with unaligned size. A local attacker could use this flaw to leak data on the XFS filesystem otherwise not accessible to them.

Metrics

CVSS 3.1

5.5/10

CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:N

EPSS Probability

0.29%

20.5th percentile

Probability of exploitation in the next 30 days. Learn more

Weakness Enumeration

Affected Software

Vendor	Product	Versions
Linux	Linux Kernel	< 5.16

References

https://access.redhat.com/security/cve/CVE-2021-4155Mitigation, Third Party Advisory
https://bugzilla.redhat.com/show_bug.cgi?id=2034813Issue Tracking, Third Party Advisory
https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=983d8e60f50806f90534cc5373d0ce867e5aaf79Mailing List, Patch, Vendor Advisory
https://security-tracker.debian.org/tracker/CVE-2021-4155Third Party Advisory
https://www.openwall.com/lists/oss-security/2022/01/10/1Mailing List, Patch, Third Party Advisory
https://access.redhat.com/security/cve/CVE-2021-4155Mitigation, Third Party Advisory
https://bugzilla.redhat.com/show_bug.cgi?id=2034813Issue Tracking, Third Party Advisory
https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=983d8e60f50806f90534cc5373d0ce867e5aaf79Mailing List, Patch, Vendor Advisory
https://security-tracker.debian.org/tracker/CVE-2021-4155Third Party Advisory
https://www.openwall.com/lists/oss-security/2022/01/10/1Mailing List, Patch, Third Party Advisory

Timeline

Published: Aug 24, 2022
Last Modified: Jun 17, 2026
Status: Modified

Frequently Asked Questions

What is CVE-2021-4155?

How severe is CVE-2021-4155?

CVE-2021-4155 has a CVSS score of 5.5/10 (MEDIUM severity). The EPSS model estimates a 0.29% probability of exploitation in the next 30 days.

How do I fix CVE-2021-4155?

Check the vendor references and advisories linked above for patched versions and mitigation guidance. You can also run a Strix scan to test if your systems are affected.

Are you affected by CVE-2021-4155?

Run a free Strix scan to check your systems for this vulnerability.

Scan your code now

Source: NVD / NIST