CVE-2020-14367
MEDIUMchrony < 3.5.1 - Denial of Service via PID File Symlink Attack
Title source: llmDescription
A flaw was found in chrony versions before 3.5.1 when creating the PID file under the /var/run/chrony folder. The file is created during chronyd startup while still running as the root user, and when it's opened for writing, chronyd does not check for an existing symbolic link with the same file name. This flaw allows an attacker with privileged access to create a symlink with the default PID file name pointing to any destination file in the system, resulting in data loss and a denial of service due to the path traversal.
References (4)
Core 4
Core References
Mailing List, Third Party Advisory vendor-advisory
x_refsource_fedora
https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/6WKABKNLCSC3MACCWU6OM2YGWVWFWFMU/
Issue Tracking, Patch, Vendor Advisory x_refsource_misc
https://bugzilla.redhat.com/show_bug.cgi?id=1870298
Third Party Advisory vendor-advisory
x_refsource_gentoo
https://security.gentoo.org/glsa/202008-23
Third Party Advisory vendor-advisory
x_refsource_ubuntu
https://usn.ubuntu.com/4475-1/
Scores
CVSS v3
6.0
EPSS
0.0027
EPSS Percentile
50.9%
Attack Vector
LOCAL
CVSS:3.1/AV:L/AC:L/PR:H/UI:N/S:U/C:N/I:H/A:H
Details
CWE
CWE-59
Status
published
Products (4)
canonical/ubuntu_linux
18.04
canonical/ubuntu_linux
20.04
fedoraproject/fedora
32
tuxfamily/chrony
< 3.5.1
Published
Aug 24, 2020
Tracked Since
Feb 18, 2026