Junos OS: MX Series: Services card might restart due to a race condition when DNS filtering is enabled.

Description

When DNS filtering is enabled on Juniper Networks Junos MX Series with one of the following cards MS-PIC, MS-MIC or MS-MPC, an incoming stream of packets processed by the Multiservices PIC Management Daemon (mspmand) process might be bypassed due to a race condition. Due to this vulnerability, mspmand process, responsible for managing "URL Filtering service", can crash, causing the Services PIC to restart. While the Services PIC is restarting, all PIC services including DNS filtering service (DNS sink holing) will be bypassed until the Services PIC completes its boot process. This issue affects Juniper Networks Junos OS: 17.3 versions prior to 17.3R3-S8; 18.3 versions prior to 18.3R3-S1; 18.4 versions prior to 18.4R3; 19.1 versions prior to 19.1R3; 19.2 versions prior to 19.2R2; 19.3 versions prior to 19.3R3. This issue does not affect Juniper Networks Junos OS 17.4, 18.1, and 18.2.

Scores

EPSS (exploitation in 30 days)

0.69% · top 47% of all CVEs (6 Nov 2026)

The list uses the assigner's score when there is one, then CISA's, then NVD's: High 8.3.

Weakness

• CWE-362 Race Condition (Concurrent Execution using Shared Resource with Improper Synchronization) (opens in a new tab)All about CWE-362 and its CVEs

Affected products

• Juniper Networks · Junos OS

  • affected 17.3 – < 17.3R3-S8
  • affected 18.3 – < 18.3R3-S1
  • affected 18.4 – < 18.4R3
  • affected 19.1 – < 19.1R3
  • affected 19.2 – < 19.2R2
  • affected 19.3 – < 19.3R3

• Juniper Networks · Junos OS

  • unaffected 17.4
  • unaffected 18.1
  • unaffected 18.2

What to do

Solution: The following software releases have been updated to resolve this specific issue: Junos OS 17.3R3-S8, 18.3R3-S1, 18.4R3, 19.1R3, 19.2R2, 19.3R3, 19.4R1, and all subsequent releases.

Workaround: There are no viable workarounds for this issue.

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

References (1)

• https://kb.juniper.net/ (opens in a new tab)x_refsource_MISCx_transferred

Sources

The same CVE in the primary databases and aggregators, to check against.

• CVE.org record (opens in a new tab)
• CVE List JSON (GitHub) (opens in a new tab)
• NVD (opens in a new tab)
• FIRST EPSS (opens in a new tab)
• OSV.dev (opens in a new tab)
• GitHub Advisories (opens in a new tab)
• CIRCL Vulnerability-Lookup (opens in a new tab)

Badge for a README or a ticket

[![CVE-2020-1667](https://trackcve.app/badge/CVE-2020-1667.svg)](https://trackcve.app/cve/CVE-2020-1667)

Record last updated 17 Sept 2024, 02:31 UTC.