How severe is CVE-2016-1550?

CVE-2016-1550 has a CVSS 3.x base score of 5.3, rated medium severity. It is exploitable over network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is low, integrity none, and availability none.

Is CVE-2016-1550 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 4% (88th percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2016-1550?

CVE-2016-1550 affects Ntp. See the affected-products list for the exact vulnerable versions.

How do I fix CVE-2016-1550?

Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround.

When was CVE-2016-1550 published?

CVE-2016-1550 was published on 2017-01-06 and last updated on 2026-06-17.

CVE-2016-1550

CVE-2016-1550 is a medium-severity vulnerability in Ntp with a CVSS 3.x base score of 5.3. It is not currently listed as actively exploited by CISA, and its EPSS exploit-prediction score is low. The underlying weakness is classified as CWE-200.

Key facts

Severity: Medium (CVSS 3.x base score 5.3)
CVSS v2: 5.0
EPSS exploit prediction: 4% (88th percentile)
Actively exploited: Not listed in CISA KEV
Weakness: CWE-200
Affected product: Ntp
Published: 2017-01-06
Last modified: 2026-06-17

Description

An exploitable vulnerability exists in the message authentication functionality of libntp in ntp 4.2.8p4 and NTPSec a5fb34b9cc89b92a8fef2f459004865c93bb7f92. An attacker can send a series of crafted messages to attempt to recover the message digest key.

Frequently asked questions

What is CVE-2016-1550?: An exploitable vulnerability exists in the message authentication functionality of libntp in ntp 4.2.8p4 and NTPSec a5fb34b9cc89b92a8fef2f459004865c93bb7f92. An attacker can send a series of crafted messages to attempt to recover the message digest key.
How severe is CVE-2016-1550?: CVE-2016-1550 has a CVSS 3.x base score of 5.3, rated medium severity. It is exploitable over network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is low, integrity none, and availability none.
Is CVE-2016-1550 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 4% (88th percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2016-1550?: CVE-2016-1550 affects Ntp. See the affected-products list for the exact vulnerable versions.
How do I fix CVE-2016-1550?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround.
When was CVE-2016-1550 published?: CVE-2016-1550 was published on 2017-01-06 and last updated on 2026-06-17.

References

Affected products (1)

cpe:2.3:a:ntp:ntp:4.2.8:p4:*:*:*:*:*:*

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Threat intelligence

Threat-intel indicators referencing this CVE:

197.248.207.139 (ipv4-addr)
135.129.128.247 (ipv4-addr)
119.201.59.224 (ipv4-addr)
125.212.244.35 (ipv4-addr)
202.29.220.126 (ipv4-addr)
93.42.227.251 (ipv4-addr)
82.209.191.11 (ipv4-addr)
119.204.60.250 (ipv4-addr)