CVE-2021-3492

Published: 15 April 2021

Shiftfs, an out-of-tree stacking file system included in Ubuntu Linux kernels, did not properly handle faults occurring during copy_from_user() correctly. These could lead to either a double-free situation or memory not being freed at all. An attacker could use this to cause a denial of service (kernel memory exhaustion) or gain privileges via executing arbitrary code. AKA ZDI-CAN-13562.

From the Ubuntu Security Team

Vincent Dehors discovered that the shiftfs file system in the Ubuntu Linux kernel did not properly handle faults in copy_from_user() when passing through ioctls to an underlying file system. A local attacker could use this to cause a denial of service (memory exhaustion) or execute arbitrary code.

Status

Severity score breakdown

References

• https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2021-3492
• https://ubuntu.com/security/notices/USN-4915-1
• https://ubuntu.com/security/notices/USN-4917-1
• NVD
• Launchpad
• Debian