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CVE-2018-8956

• Severity: medium (CVSS 5.3 v3.1)
• Exploited in the wild: not listed in CISA KEV
• EPSS: 3.1% probability of exploitation in the next 30 days
• Public exploit or detection template: none known
• Published: 2020-05-06 · updated 2026-06-17
• Weakness: CWE-20

Description

ntpd in ntp 4.2.8p10, 4.2.8p11, 4.2.8p12 and 4.2.8p13 allow remote attackers to prevent a broadcast client from synchronizing its clock with a broadcast NTP server via soofed mode 3 and mode 5 packets. The attacker must either be a part of the same broadcast network or control a slave in that broadcast network that can capture certain required packets on the attacker's behalf and send them to the attacker.

Affected products

• NTP: 4.2.8-p10, 4.2.8-p11, 4.2.8-p12, 4.2.8-p13

References

• http://lists.opensuse.org/opensuse-security-announce/2020-07/msg00005.html
• http://lists.opensuse.org/opensuse-security-announce/2020-07/msg00044.html
• http://www.ntp.org/
• https://arxiv.org/abs/2005.01783
• https://nikhiltripathi.in/NTP_attack.pdf
• https://security.netapp.com/advisory/ntap-20200518-0006/
• https://tools.ietf.org/html/rfc5905
• http://lists.opensuse.org/opensuse-security-announce/2020-07/msg00005.html
• http://lists.opensuse.org/opensuse-security-announce/2020-07/msg00044.html
• http://www.ntp.org/
• https://arxiv.org/abs/2005.01783
• https://nikhiltripathi.in/NTP_attack.pdf

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