Chrony
CVE-2020-14367
MEDIUM
Vulnerability Assessment
| Weakness |
CWE
OWASP Top 10:2025
A01:2025 - Broken Access Control
ASVS 5.0
V5 - File Handling Symlink resolution safety
|
| Impact | CVSS score of 6.0 (MEDIUM). Attack characteristics: local attack vector, low complexity, high privileges required, no user interaction not required. |
| Exploit ScenarioDerived | Successful exploitation could compromise the medium-severity affected system. |
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Alert meAnalysisAI
A flaw was found in chrony versions before 3.5.1 when creating the PID file under the /var/run/chrony folder. Rated medium severity (CVSS 6.0), this vulnerability is low attack complexity.
RemediationAI
A vendor patch is available. Apply the latest security update as soon as possible. Apply vendor patches when available. Implement network segmentation and monitoring as interim mitigations.
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Technical ContextAI · show details
This vulnerability is classified under CWE-59. 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. Affected products include: Tuxfamily Chrony, Fedoraproject Fedora, Canonical Ubuntu Linux. Version information: before 3.5.1.
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Severity by source
AV:L/AC:L/PR:H/UI:N/S:U/C:N/I:H/A:H
Primary rating from NVD · only source for this CVE.
CVSS VectorNVD
DescriptionNVD
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.
Threat Intelligence Overview
NVD
CVE.org
EPSS
How this decision was reached
The engine reads each signal below and applies a fixed list of rules from top to bottom. The first rule that matches sets the recommended action – like a statement, every line is shown.
What every action level means
SSVC AssessmentENISA
Priority Score
Attack Technique
Path traversal exploits occur when applications use user-controlled input to construct file system paths without proper validation.
Denial of Service attacks render applications or systems unavailable by overwhelming resources or triggering failure conditions.
Affected Products (CPE)NVD
chrony before 1.31.2 and 2.x before 2.2.1 do not verify peer associations of symmetric keys when authenticating packets,
Heap-based buffer overflow in chrony before 1.31.1 allows remote authenticated users to cause a denial of service (chron
chrony before 1.31.1 does not initialize the last "next" pointer when saving unacknowledged replies to command requests,
Multiple integer overflows in pktlength.c in Chrony before 1.29 allow remote attackers to cause a denial of service (cra
cmdmon.c in Chrony before 1.29 allows remote attackers to obtain potentially sensitive information from stack memory via
GitHub PoC
Exploit-DB