CVE-2009-3563
6.4
CVSS v2.0 Base Score
81.11%
HIGH RiskEPSS (99th percentile)
NVD-CWE-Other
ntp_request.c in ntpd in NTP before 4.2.4p8, and 4.2.5, allows remote attackers to cause a denial of service (CPU and bandwidth consumption) by using MODE_PRIVATE to send a spoofed (1) request or (2) response packet that triggers a continuous exchange of MODE_PRIVATE error responses between two NTP daemons.
Published: 12/9/2009
Modified: 4/23/2026
Vulnerability Summary
CVSS v2 Score
6.4
AV:N/AC:L/Au:N/C:N/I:P/A:P
EPSS Score (Exploitation Probability)
81.11%HIGH Exploitation Risk
99th percentile
This vulnerability has a 81.11% probability of being exploited in the next 30 days, ranking higher than 99% of all scored CVEs.
CWE Classification
NVD-CWE-Other