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2018-01 Security Bulletin: Junos OS: Kernel Denial of Service Vulnerability (CVE-2018-0004)

Product Affected:
This issue affects Junos OS 12.1X46, 12.3R, 12.3X48, 14.1, 14.1X53, 14.2, 15.1, 15.1X49, 15.1X53.

A sustained sequence of different types of normal transit traffic can trigger a high CPU consumption denial of service condition in the Junos OS register and schedule software interrupt handler subsystem when a specific command is issued to the device.  This affects one or more threads and conversely one or more running processes running on the system.  Once this occurs, the high CPU event(s) affects either or both the forwarding and control plane.  As a result of this condition the device can become inaccessible in either or both the control and forwarding plane and stops forwarding traffic until the device is rebooted.  Score: 5.7 MEDIUM (CVSS:3.0/AV:A/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:H)  

For network designs utilizing layer 3 forwarding agents or other ARP through layer 3 technologies, the score is slightly higher.  Score: 6.5 MEDIUM (CVSS:3.0/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:H)  

The issue will reoccur after reboot upon receiving further transit traffic.

If the following entry exists in the RE message logs then this may indicate the issue is present. This entry may or may not appear when this issue occurs.

/kernel: Expensive timeout(9) function:

Affected releases are Juniper Networks Junos OS:

  • 12.1X46 versions prior to 12.1X46-D50;
  • 12.3X48 versions prior to 12.3X48-D30;
  • 12.3R versions prior to 12.3R12-S7;
  • 14.1 versions prior to 14.1R8-S4, 14.1R9;
  • 14.1X53 versions prior to 14.1X53-D30, 14.1X53-D34;
  • 14.2 versions prior to 14.2R8;
  • 15.1 versions prior to 15.1F6, 15.1R3;
  • 15.1X49 versions prior to 15.1X49-D40;
  • 15.1X53 versions prior to 15.1X53-D31, 15.1X53-D33, 15.1X53-D60.

No other Juniper Networks products or platforms are affected by this issue.

Juniper SIRT is not aware of any malicious exploitation of this vulnerability.

This issue was seen in a production network.

This issue has been assigned CVE-2018-0004.


The following software releases have been updated to resolve this specific issue: 12.1X46-D50, 12.3R12-S7, 12.3X48-D30, 14.1R8-S4, 14.1R9, 14.1X53-D30, 14.1X53-D34, 14.2R8, 15.1F6, 15.1R3, 15.1X49-D40, 15.1X53-D31, 15.1X53-D33, 15.1X53-D60, 16.1R1, and all subsequent releases.

This issue is being tracked as 1145306 which is visible on the Customer Support website.

Note: Juniper SIRT's policy is not to evaluate releases which are beyond End of Engineering (EOE) or End of Life (EOL).

There are no viable workarounds for this issue.
Software Releases, patches and updates are available at
Modification History:
2018-01-10: Initial publication
Related Links:
CVSS Score:
6.5 (CVSS:3.0/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:H)
Severity Level:
Severity Assessment:
Information for how Juniper Networks uses CVSS can be found at KB 16446 "Common Vulnerability Scoring System (CVSS) and Juniper's Security Advisories."