CVE-2018-6954

Publication date 13 February 2018

Last updated 24 July 2024

Ubuntu priority

Medium

Why this priority?

Cvss 3 Severity Score

7.8 · High

Score breakdown

systemd-tmpfiles in systemd through 237 mishandles symlinks present in non-terminal path components, which allows local users to obtain ownership of arbitrary files via vectors involving creation of a directory and a file under that directory, and later replacing that directory with a symlink. This occurs even if the fs.protected_symlinks sysctl is turned on.

Read the notes from the security team

Status

Package Ubuntu Release Status
systemd 18.10 cosmic
Fixed 239-7ubuntu10.4
18.04 LTS bionic
Fixed 237-3ubuntu10.9
17.10 artful Ignored end of life
16.04 LTS xenial
Fixed 229-4ubuntu21.15
14.04 LTS trusty
Not affected

Notes

mdeslaur

original fix was incomplete, see second pull

chrisccoulson

Fix reverted in xenial because it breaks containers running on pre-2.6.39 kernels

mdeslaur

fix was re-introduced in xenial in 229-4ubuntu21.15

Patch details

For informational purposes only. We recommend not to cherry-pick updates. How can I get the fixes?

Package Patch details
systemd

Severity score breakdown

Parameter Value
Base score 7.8 · High
Attack vector Local
Attack complexity Low
Privileges required Low
User interaction None
Scope Unchanged
Confidentiality High
Integrity impact High
Availability impact High
Vector CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H

References

Related Ubuntu Security Notices (USN)

    • USN-3816-1
    • systemd vulnerabilities
    • 12 November 2018
    • USN-3816-2
    • systemd vulnerability
    • 19 November 2018

Other references