CVE-2021-20321

Description

A race condition accessing file object in the Linux kernel OverlayFS subsystem was found in the way users do rename in specific way with OverlayFS. A local user could use this flaw to crash the system.

CVSS Metrics

• v3.1•MEDIUM•Score: 4.7CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:N/I:N/A:H
• v2.0•MEDIUM•Score: 4.7AV:L/AC:M/Au:N/C:N/I:N/A:C

EPSS Trends

Current EPSS score: 0.02%• Percentile: 5%

Techniques & Countermeasures

• CWE-362•Concurrent Execution using Shared Resource with Improper Synchronization ('Race Condition')

  The product contains a concurrent code sequence that requires temporary, exclusive access to a shared resource, but a timing window exists in which the shared resource can be modified by another code sequence operating concurrently.

Affected Systems

• debian•debian_linux

  9.0 | 10.0

• linux•linux_kernel

  < 5.15 | 5.15 | 5.15:rc1 | 5.15:rc2 | 5.15:rc3 | 5.15:rc4

• redhat•enterprise_linux

  7.0 | 8.0

References (4)

• https://bugzilla.redhat.com/show_bug.cgi?id=2013242
• https://lore.kernel.org/all/20211011134508.748956131%40linuxfoundation.org/
• https://lists.debian.org/debian-lts-announce/2022/03/msg00012.html
• https://www.debian.org/security/2022/dsa-5096