How severe is CVE-2016-4957?

CVE-2016-4957 has a CVSS 3.x base score of 7.5, rated high severity. It is exploitable over network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is none, integrity none, and availability high.

Is CVE-2016-4957 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 45% (99th percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2016-4957?

CVE-2016-4957 primarily affects Ntp. In total, 14 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.

How do I fix CVE-2016-4957?

Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its high severity, prioritise patching exposed systems.

When was CVE-2016-4957 published?

CVE-2016-4957 was published on 2016-07-05 and last updated on 2026-06-17.

CVE-2016-4957

CVE-2016-4957 is a high-severity vulnerability in Ntp with a CVSS 3.x base score of 7.5. Its EPSS exploit-prediction score of 45% places it in the 99th percentile, indicating an elevated likelihood of exploitation. The underlying weakness is classified as CWE-476.

Key facts

Severity: High (CVSS 3.x base score 7.5)
CVSS v2: 5.0
EPSS exploit prediction: 45% (99th percentile)
Actively exploited: Not listed in CISA KEV
Weakness: CWE-476
Affected product: Ntp
Published: 2016-07-05
Last modified: 2026-06-17

Description

ntpd in NTP before 4.2.8p8 allows remote attackers to cause a denial of service (daemon crash) via a crypto-NAK packet. NOTE: this vulnerability exists because of an incorrect fix for CVE-2016-1547.

Frequently asked questions

What is CVE-2016-4957?: ntpd in NTP before 4.2.8p8 allows remote attackers to cause a denial of service (daemon crash) via a crypto-NAK packet. NOTE: this vulnerability exists because of an incorrect fix for CVE-2016-1547.
How severe is CVE-2016-4957?: CVE-2016-4957 has a CVSS 3.x base score of 7.5, rated high severity. It is exploitable over network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is none, integrity none, and availability high.
Is CVE-2016-4957 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 45% (99th percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2016-4957?: CVE-2016-4957 primarily affects Ntp. In total, 14 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.
How do I fix CVE-2016-4957?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its high severity, prioritise patching exposed systems.
When was CVE-2016-4957 published?: CVE-2016-4957 was published on 2016-07-05 and last updated on 2026-06-17.

References

Affected products (14)

cpe:2.3:a:ntp:ntp:4.2.8:p7:*:*:*:*:*:*
cpe:2.3:a:ntp:ntp:4.3.92:*:*:*:*:*:*:*
cpe:2.3:o:oracle:solaris:10:*:*:*:*:*:*:*
cpe:2.3:o:oracle:solaris:11.3:*:*:*:*:*:*:*
cpe:2.3:a:suse:manager_proxy:2.1:*:*:*:*:*:*:*
cpe:2.3:a:suse:openstack_cloud:5:*:*:*:*:*:*:*
cpe:2.3:o:novell:suse_manager:2.1:*:*:*:*:*:*:*
cpe:2.3:o:opensuse:leap:42.1:*:*:*:*:*:*:*
cpe:2.3:o:opensuse:opensuse:13.2:*:*:*:*:*:*:*
cpe:2.3:o:suse:linux_enterprise_desktop:12:sp1:*:*:*:*:*:*
cpe:2.3:o:suse:linux_enterprise_server:11:sp2:*:*:ltss:*:*:*
cpe:2.3:o:suse:linux_enterprise_server:11:sp3:*:*:ltss:*:*:*
cpe:2.3:o:suse:linux_enterprise_server:11:sp4:*:*:*:*:*:*
cpe:2.3:o:suse:linux_enterprise_server:12:sp1:*:*:*:*:*:*

More vulnerabilities in Ntp

CVE-2018-12327 — Critical (CVSS 9.8): Stack-based buffer overflow in ntpq and ntpdc of NTP version 4.2.8p11 allows an attacker to achieve code execution or…
CVE-2018-7183 — Critical (CVSS 9.8): Buffer overflow in the decodearr function in ntpq in ntp 4.2.8p6 through 4.2.8p10 allows remote attackers to execute…
CVE-2015-7871 — Critical (CVSS 9.8): Crypto-NAK packets in ntpd in NTP 4.2.x before 4.2.8p4, and 4.3.x before 4.3.77 allows remote attackers to bypass…
CVE-2015-7853 — Critical (CVSS 9.8): The datalen parameter in the refclock driver in NTP 4.2.x before 4.2.8p4, and 4.3.x before 4.3.77 allows remote…
CVE-2015-7705 — Critical (CVSS 9.8): The rate limiting feature in NTP 4.x before 4.2.8p4 and 4.3.x before 4.3.77 allows remote attackers to have unspecified…
CVE-2015-7854 — High (CVSS 8.8): Buffer overflow in the password management functionality in NTP 4.2.x before 4.2.8p4, and 4.3.x before 4.3.77 allows…

All CVEs affecting Ntp →

Other CWE-476 (NULL Pointer Dereference) vulnerabilities

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CVE-2020-14500 — Critical (CVSS 10.0): Secomea GateManager all versions prior to 9.2c, An attacker can send a negative value and overwrite arbitrary data.
CVE-2010-2495 — Critical (CVSS 10.0): The pppol2tp_xmit function in drivers/net/pppol2tp.c in the L2TP implementation in the Linux kernel before 2.6.34 does…
CVE-2026-46195 — Critical (CVSS 9.8): In the Linux kernel, the following vulnerability has been resolved: smb: client: validate dacloffset before building…
CVE-2026-31657 — Critical (CVSS 9.8): In the Linux kernel, the following vulnerability has been resolved: batman-adv: hold claim backbone gateways by…
CVE-2026-31436 — Critical (CVSS 9.8): In the Linux kernel, the following vulnerability has been resolved: dmaengine: idxd: fix possible wrong descriptor…

Browse all CWE-476 (NULL Pointer Dereference) vulnerabilities →

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)