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CVE-2018-7183

Buffer overflow in the decodearr function in ntpq in ntp 4.2.8p6 through 4.2.8p10 allows remote...

9.8 CriticalFix available

Buffer overflow in the decodearr function in ntpq in ntp 4.2.8p6 through 4.2.8p10 allows remote attackers to execute arbitrary code by leveraging an ntpq query and sending a response with a crafted array.

Attack profile

How easy it is to exploit

Attack vector
Network
Complexity
Low
Privileges needed
None
User interaction
None

What an attacker can affect

Confidentiality
High
Integrity
High
Availability
High

Exploit likelihood

10.2%Up 5.3 points since Apr 14, 2021
90%50%10%1%

What each source reports

NVD Score used 9.8

Buffer overflow in the decodearr function in ntpq in ntp 4.2.8p6 through 4.2.8p10 allows remote attackers to execute arbitrary code by leveraging an ntpq query and sending a response with a crafted array.

Record
CVE-2018-7183
CVSS 3.0
9.8 CriticalCVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
CVSS 2.0
7.5 HighAV:N/AC:L/Au:N/C:P/I:P/A:P
Weakness
CWE-787
Updated
2026-11-02
CVE List No score

Buffer overflow in the decodearr function in ntpq in ntp 4.2.8p6 through 4.2.8p10 allows remote attackers to execute arbitrary code by leveraging an ntpq query and sending a response with a crafted array.

Record
CVE-2018-7183
Updated
2026-11-02
EUVDEUVD-2018-18925 No score

Buffer overflow in the decodearr function in ntpq in ntp 4.2.8p6 through 4.2.8p10 allows remote attackers to execute arbitrary code by leveraging an ntpq query and sending a response with a crafted array.

Record
EUVD-2018-18925
Updated
2026-11-03
GitHub AdvisoriesGHSA-9429-whv8-4h3p 9.8

Buffer overflow in the decodearr function in ntpq in ntp 4.2.8p6 through 4.2.8p10 allows remote...

Buffer overflow in the decodearr function in ntpq in ntp 4.2.8p6 through 4.2.8p10 allows remote attackers to execute arbitrary code by leveraging an ntpq query and sending a response with a crafted array.

Record
GHSA-9429-whv8-4h3p
CVSS 3.0
9.8 CriticalCVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
Weakness
CWE-787
Updated
2026-11-02
OSV 9.8

Buffer overflow in the decodearr function in ntpq in ntp 4.2.8p6 through 4.2.8p10 allows remote attackers to execute arbitrary code by leveraging an ntpq query and sending a response with a crafted array.

Record
CVE-2018-7183
CVSS 3.0
9.8 CriticalCVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
Updated
2026-11-02
OSVDEBIAN-CVE-2018-7183 9.8

Buffer overflow in the decodearr function in ntpq in ntp 4.2.8p6 through 4.2.8p10 allows remote attackers to execute arbitrary code by leveraging an ntpq query and sending a response with a crafted array.

Record
DEBIAN-CVE-2018-7183
CVSS 3.0
9.8 CriticalCVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
Updated
2026-11-02
Show 9 moreShow less
OSVUBUNTU-CVE-2018-7183 9.8

Buffer overflow in the decodearr function in ntpq in ntp 4.2.8p6 through 4.2.8p10 allows remote attackers to execute arbitrary code by leveraging an ntpq query and sending a response with a crafted array.

Record
UBUNTU-CVE-2018-7183
CVSS 3.0
9.8 CriticalCVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
Updated
2026-11-02
OSVMGASA-2018-0195 No score

Updated ntp packages fix security vulnerabilities

This release addresses five security issues in ntpd for Mageia 6:

LOW/MEDIUM: Sec 3012 / CVE-2016-1549 / VU#961909: Sybil vulnerability: ephemeral association attack While fixed in ntp-4.2.8p7, there are significant additional protections for this issue in 4.2.8p11. Reported by Matt Van Gundy of Cisco.

INFO/MEDIUM: Sec 3412 / CVE-2018-7182 / VU#961909: ctl_getitem(): buffer read overrun leads to undefined behavior and information leak Reported by Yihan Lian of Qihoo 360.

LOW: Sec 3415 / CVE-2018-7170 / VU#961909: Multiple authenticated ephemeral associations. Reported on the questions@ list.

LOW: Sec 3453 / CVE-2018-7184 / VU#961909: Interleaved symmetric mode cannot recover from bad state. Reported by Miroslav Lichvar of Red Hat.

LOW/MEDIUM: Sec 3454 / CVE-2018-7185 / VU#961909: Unauthenticated packet can reset authenticated interleaved association. Reported by Miroslav Lichvar of Red Hat.

one security issue in ntpq: MEDIUM: Sec 3414 / CVE-2018-7183 / VU#961909: ntpq:decodearr() can write beyond its buffer limit. Reported by Michael Macnair of Thales-esecurity.com.

and provides over 33 bugfixes and 32 other improvements. ENotification of these issues were delivered to our Institutional members on a rolling basis as they were reported and as progress was made.

Record
MGASA-2018-0195
Updated
2026-11-02
OSVopenSUSE-SU-2024:11102-1 No score

ntp-4.2.8p15-7.2 on GA media

These are all security issues fixed in the ntp-4.2.8p15-7.2 package on the GA media of openSUSE Tumbleweed.

Record
openSUSE-SU-2024:11102-1
Updated
2026-11-02
OSVSUSE-SU-2018:0808-1 No score

Security update for ntp

This update for ntp fixes the following issues:

Security issues fixed:

  • CVE-2016-1549: Significant additional protections against CVE-2016-1549 that was fixed in ntp-4.2.8p7 (bsc#1082210).
  • CVE-2018-7170: Ephemeral association time spoofing additional protection (bsc#1083424).
  • CVE-2018-7182: Buffer read overrun leads information leak in ctl_getitem() (bsc#1083426).
  • CVE-2018-7183: decodearr() can write beyond its buffer limit (bsc#1083417).
  • CVE-2018-7184: Interleaved symmetric mode cannot recover from bad state (bsc#1083422).
  • CVE-2018-7185: Unauthenticated packet can reset authenticated interleaved association (bsc#1083420).

Bug fixes:

  • bsc#1077445: Don't use libevent's cached time stamps in sntp.
  • Disable CMAC in ntp when building against a version of OpenSSL that doesn't support it.
Record
SUSE-SU-2018:0808-1
Updated
2026-11-02
OSVSUSE-SU-2018:0956-1 No score

Security update for ntp

This update for ntp fixes the following issues:

  • Update to 4.2.8p11 (bsc#1082210):
    • CVE-2016-1549: Sybil vulnerability: ephemeral association attack. While fixed in ntp-4.2.8p7, there are significant additional protections for this issue in 4.2.8p11.
    • CVE-2018-7182: ctl_getitem(): buffer read overrun leads to undefined behavior and information leak. (bsc#1083426)
    • CVE-2018-7170: Multiple authenticated ephemeral associations. (bsc#1083424)
    • CVE-2018-7184: Interleaved symmetric mode cannot recover from bad state. (bsc#1083422)
    • CVE-2018-7185: Unauthenticated packet can reset authenticated interleaved association. (bsc#1083420)
    • CVE-2018-7183: ntpq:decodearr() can write beyond its buffer limit.(bsc#1083417)
  • Don't use libevent's cached time stamps in sntp. (bsc#1077445)
Record
SUSE-SU-2018:0956-1
Updated
2026-11-02
OSVSUSE-SU-2018:1464-1 No score

Security update for ntp

This update for ntp fixes the following issues:

  • Update to 4.2.8p11 (bsc#1082210):
    • CVE-2016-1549: Sybil vulnerability: ephemeral association attack. While fixed in ntp-4.2.8p7, there are significant additional protections for this issue in 4.2.8p11.
    • CVE-2018-7182: ctl_getitem(): buffer read overrun leads to undefined behavior and information leak. (bsc#1083426)
    • CVE-2018-7170: Multiple authenticated ephemeral associations. (bsc#1083424)
    • CVE-2018-7184: Interleaved symmetric mode cannot recover from bad state. (bsc#1083422)
    • CVE-2018-7185: Unauthenticated packet can reset authenticated interleaved association. (bsc#1083420)
    • CVE-2018-7183: ntpq:decodearr() can write beyond its buffer limit.(bsc#1083417)
  • Don't use libevent's cached time stamps in sntp. (bsc#1077445)
  • Fix systemd migration in %pre (bsc#1034892).
Record
SUSE-SU-2018:1464-1
Updated
2026-11-02
OSVSUSE-SU-2018:1765-1 No score

Security update for ntp

This update for ntp fixes the following issues:

  • Update to 4.2.8p11 (bsc#1082210):
    • CVE-2016-1549: Sybil vulnerability: ephemeral association attack. While fixed in ntp-4.2.8p7, there are significant additional protections for this issue in 4.2.8p11.
    • CVE-2018-7182: ctl_getitem(): buffer read overrun leads to undefined behavior and information leak. (bsc#1083426)
    • CVE-2018-7170: Multiple authenticated ephemeral associations. (bsc#1083424)
    • CVE-2018-7184: Interleaved symmetric mode cannot recover from bad state. (bsc#1083422)
    • CVE-2018-7185: Unauthenticated packet can reset authenticated interleaved association. (bsc#1083420)
    • CVE-2018-7183: ntpq:decodearr() can write beyond its buffer limit.(bsc#1083417)
  • Don't use libevent's cached time stamps in sntp. (bsc#1077445)

This update is a reissue of the previous update with LTSS channels included.

Record
SUSE-SU-2018:1765-1
Updated
2026-11-02
OSVSUSE-SU-2018:1765-2 No score

Security update for ntp

This update for ntp fixes the following issues:

  • Update to 4.2.8p11 (bsc#1082210):
    • CVE-2016-1549: Sybil vulnerability: ephemeral association attack. While fixed in ntp-4.2.8p7, there are significant additional protections for this issue in 4.2.8p11.
    • CVE-2018-7182: ctl_getitem(): buffer read overrun leads to undefined behavior and information leak. (bsc#1083426)
    • CVE-2018-7170: Multiple authenticated ephemeral associations. (bsc#1083424)
    • CVE-2018-7184: Interleaved symmetric mode cannot recover from bad state. (bsc#1083422)
    • CVE-2018-7185: Unauthenticated packet can reset authenticated interleaved association. (bsc#1083420)
    • CVE-2018-7183: ntpq:decodearr() can write beyond its buffer limit.(bsc#1083417)
  • Don't use libevent's cached time stamps in sntp. (bsc#1077445)

This update is a reissue of the previous update with LTSS channels included.

Record
SUSE-SU-2018:1765-2
Updated
2026-11-02
OSVUSN-3707-1 No score

ntp vulnerabilities

Yihan Lian discovered that NTP incorrectly handled certain malformed mode 6 packets. A remote attacker could possibly use this issue to cause ntpd to crash, resulting in a denial of service. This issue only affected Ubuntu 17.10 and Ubuntu 18.04 LTS. (CVE-2018-7182)

Michael Macnair discovered that NTP incorrectly handled certain responses. A remote attacker could possibly use this issue to execute arbitrary code. (CVE-2018-7183)

Miroslav Lichvar discovered that NTP incorrectly handled certain zero-origin timestamps. A remote attacker could possibly use this issue to cause a denial of service. This issue only affected Ubuntu 17.10 and Ubuntu 18.04 LTS. (CVE-2018-7184)

Miroslav Lichvar discovered that NTP incorrectly handled certain zero-origin timestamps. A remote attacker could possibly use this issue to cause a denial of service. (CVE-2018-7185)

Record
USN-3707-1
Updated
2026-11-02

Affected products

Affected packages

Affected packages
PackageAffectedFixed
ntp
Debian:11
before 1:4.2.8p11+dfsg-1
1:4.2.8p11+dfsg-1
ntp
Mageia:6
before 4.2.8p11-1.mga6
4.2.8p11-1.mga6
ntp
SUSE:Linux Enterprise Server 11 SP4
before 4.2.8p11-64.4.1
4.2.8p11-64.4.1
ntp
SUSE:Linux Enterprise Server for SAP Applications 11 SP4
before 4.2.8p11-64.4.1
4.2.8p11-64.4.1
ntp
SUSE:Linux Enterprise Desktop 12 SP3
before 4.2.8p11-64.3.2
4.2.8p11-64.3.2
ntp
SUSE:Linux Enterprise Server 12 SP3
before 4.2.8p11-64.3.2
4.2.8p11-64.3.2
ntp
SUSE:Linux Enterprise Server for SAP Applications 12 SP3
before 4.2.8p11-64.3.2
4.2.8p11-64.3.2
ntp
SUSE:Linux Enterprise Server 12-LTSS
before 4.2.8p11-46.26.2
4.2.8p11-46.26.2
ntp
SUSE:OpenStack Cloud 7
before 4.2.8p11-64.5.1
4.2.8p11-64.5.1
ntp
SUSE:Linux Enterprise Desktop 12 SP3
before 4.2.8p11-64.5.1
4.2.8p11-64.5.1
Show 12 moreShow less
Affected packages
PackageAffectedFixed
ntp
SUSE:Linux Enterprise Server for SAP Applications 12 SP1
before 4.2.8p11-64.5.1
4.2.8p11-64.5.1
ntp
SUSE:Linux Enterprise Server for SAP Applications 12 SP2
before 4.2.8p11-64.5.1
4.2.8p11-64.5.1
ntp
SUSE:Linux Enterprise Server 12 SP1-LTSS
before 4.2.8p11-64.5.1
4.2.8p11-64.5.1
ntp
SUSE:Linux Enterprise Server 12 SP2-LTSS
before 4.2.8p11-64.5.1
4.2.8p11-64.5.1
ntp
SUSE:Linux Enterprise Server 12 SP3
before 4.2.8p11-64.5.1
4.2.8p11-64.5.1
ntp
SUSE:Linux Enterprise Server for SAP Applications 12 SP3
before 4.2.8p11-64.5.1
4.2.8p11-64.5.1
ntp
SUSE:Enterprise Storage 4
before 4.2.8p11-64.5.1
4.2.8p11-64.5.1
ntp
SUSE:Linux Enterprise Server 12 SP2-BCL
before 4.2.8p11-64.5.1
4.2.8p11-64.5.1
ntp
Ubuntu:14.04:LTS
before 1:4.2.6.p5+dfsg-3ubuntu2.14.04.13, plus listed versions
1:4.2.6.p5+dfsg-3ubuntu21:4.2.6.p5+dfsg-3ubuntu2.14.04.11:4.2.6.p5+dfsg-3ubuntu2.14.04.21:4.2.6.p5+dfsg-3ubuntu2.14.04.31:4.2.6.p5+dfsg-3ubuntu2.14.04.5
Show 6 moreShow less
1:4.2.6.p5+dfsg-3ubuntu2.14.04.61:4.2.6.p5+dfsg-3ubuntu2.14.04.71:4.2.6.p5+dfsg-3ubuntu2.14.04.81:4.2.6.p5+dfsg-3ubuntu2.14.04.101:4.2.6.p5+dfsg-3ubuntu2.14.04.111:4.2.6.p5+dfsg-3ubuntu2.14.04.12
1:4.2.6.p5+dfsg-3ubuntu2.14.04.13
ntp
Ubuntu:16.04:LTS
before 1:4.2.8p4+dfsg-3ubuntu5.9, plus listed versions
1:4.2.6.p5+dfsg-3ubuntu81:4.2.6.p5+dfsg-3ubuntu8.11:4.2.6.p5+dfsg-3ubuntu91:4.2.8p4+dfsg-3ubuntu11:4.2.8p4+dfsg-3ubuntu2
Show 11 moreShow less
1:4.2.8p4+dfsg-3ubuntu31:4.2.8p4+dfsg-3ubuntu41:4.2.8p4+dfsg-3ubuntu51:4.2.8p4+dfsg-3ubuntu5.11:4.2.8p4+dfsg-3ubuntu5.21:4.2.8p4+dfsg-3ubuntu5.31:4.2.8p4+dfsg-3ubuntu5.41:4.2.8p4+dfsg-3ubuntu5.51:4.2.8p4+dfsg-3ubuntu5.61:4.2.8p4+dfsg-3ubuntu5.71:4.2.8p4+dfsg-3ubuntu5.8
1:4.2.8p4+dfsg-3ubuntu5.9
ntp
Ubuntu:18.04:LTS
before 1:4.2.8p10+dfsg-5ubuntu7.1, plus listed versions
1:4.2.8p10+dfsg-5ubuntu31:4.2.8p10+dfsg-5ubuntu41:4.2.8p10+dfsg-5ubuntu51:4.2.8p10+dfsg-5ubuntu61:4.2.8p10+dfsg-5ubuntu7
1:4.2.8p10+dfsg-5ubuntu7.1
ntp
openSUSE:Tumbleweed
before 4.2.8p15-7.2
4.2.8p15-7.2

History

History
RecordedChangedSources
aliasesEUVD
first indexedCVE List, GitHub Advisories, NVD, OSV

Dates are when Every CVE recorded each change. Upstream dates may differ.

In short

CVE-2018-7183 is a critical vulnerability (CVSS 9.8) in Ntp, published March 8, 2018. No source lists public exploit code. EPSS puts the chance of exploitation in the next 30 days at 10.2%, the 95th percentile. Fixed in ntp 1:4.2.8p11+dfsg-1.

References

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