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2018-10 Security Bulletin: Junos OS: Nexthop index allocation failed: private index space exhausted via incoming ARP requests to management interface (CVE-2018-0063)

  [JSA10899] Show Article Properties

Product Affected:
This issue affects Junos OS 17.3R3.

A vulnerability in the IP next-hop index database in Junos OS 17.3R3 may allow a flood of ARP requests, sent to the management interface, to exhaust the private Internal routing interfaces (IRIs) next-hop limit. Once the IRI next-hop database is full, no further next hops can be learned and existing entries cannot be cleared, leading to a sustained denial of service (DoS) condition.

An indicator of compromise for this issue is the report of the following error message:

%KERN-4: Nexthop index allocation failed: private index space exhausted

This issue only affects the management interface, and does not impact regular transit traffic through the FPCs.

This issue also only affects Junos OS 17.3R3. No prior versions of Junos OS are affected by this issue.

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

This issue was seen during production usage.

This issue has been assigned CVE-2018-0063.


The following software releases have been updated to recover from private index space exhaustion: 17.3R3-S1 and all subsequent releases.

This issue is being tracked as PR 1360039 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:
2018-10-10: Initial Publication

Related Links:
CVSS Score:
6.5 (CVSS:3.0/AV:A/AC:L/PR:N/UI:N/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."