CVE-2019-15793

Mishandling of file-system uid/gid with namespaces in shiftfs

In shiftfs, a non-upstream patch to the Linux kernel included in the Ubuntu 5.0 and 5.3 kernel series, several locations which shift ids translate user/group ids before performing operations in the lower filesystem were translating them into init_user_ns, whereas they should have been translated into the s_user_ns for the lower filesystem. This resulted in using ids other than the intended ones in the lower fs, which likely did not map into the shifts s_user_ns. A local attacker could use this to possibly bypass discretionary access control permissions.

Affected

Ubuntu · Shiftfs in the Linux kernel

CVSS v3.1 NVD

8.8 HIGHCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H

CVSS v3.1 UBUNTU

6.5 MEDIUMCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:C/C:H/I:N/A:N

CVSS v2.0 NVD

4.6 MEDIUMAV:L/AC:L/Au:N/C:P/I:P/A:P

EPSS

0.69% chance of exploitation in the next 30 days, 52nd percentile

Published

2020-04-23

Updated

2024-09-16

ExploitDB entries (1)

• https://www.exploit-db.com/exploits/47693

Security advisories

• https://git.launchpad.net/~ubuntu-kernel/ubuntu/+source/linux/+git/eoan/commit/?id=3644b9…
• https://usn.ubuntu.com/usn/usn-4183-1
• https://usn.ubuntu.com/usn/usn-4184-1

References

• CVE Record
• NVD entry