What is CVE-2020-1645?

CVE-2020-1645 is a high-severity vulnerability in Juniper Junos, classified under Concurrent Execution using Shared Resource with Improper Synchronization (Race Condition). CVSS score: 8.3/10. Published 2020-07-17.

How severe is CVE-2020-1645?

High severity. CVSS v3 base score is 8.3 out of 10.

Vulnerability in Juniper Junos

CVE-2020-1645

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, responsible for managing "URL Filtering service", may 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. If the issue occurs, system core-dumps output will show a crash of mspmand process: root@device> show system core-dumps -rw-rw---- 1 nobody wheel 575685123 <Date> /var/tmp/pics/mspmand.core.<*>.gz This issue affects Juniper Networks Junos OS: 17.3 versions prior to 17.3R3-S8; 18.3 versions prior to 18.3R2-S4, 18.3R3-S1; 18.4 versions prior to 18.4R2-S5, 18.4R3; 19.1 versions prior to 19.1R2-S2, 19.1R3; 19.2 versions prior to 19.2R1-S5, 19.2R2; 19.3 versions prior to 19.3R2-S3, 19.3R3; 19.4 versions prior to 19.4R1-S3, 19.4R2. This issue does not affect Juniper Networks Junos OS releases prior to 17.3R2.

Vulnerability class: Race Condition

Published 2020-07-17 · last modified 2026-06-17.

CVSS v3 metric

CVSS v3 base score 8.3 (High). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:L/I:L/A:L.

EPSS exploit prediction

EPSS: 0.006 (48.2th percentile), scored 2026-10-03.

Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 48th percentile — 48.2% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.

EPSS over last 30 days · oldest: 0.006 · newest: 0.006 · change: 0.000

Affected products

Juniper Junos — versions 17.3, 18.3, 18.4
Juniper Networks Junos OS — versions unspecified, 17.4, 18.1

Weakness classification (CWE)

CWE-362 — Concurrent Execution using Shared Resource with Improper Synchronization (Race Condition)

References

kb.juniper.net/JSA11028 (Vendor Advisory)

Frequently asked questions

What is CVE-2020-1645?: CVE-2020-1645 is a high-severity vulnerability in Juniper Junos, classified under Concurrent Execution using Shared Resource with Improper Synchronization (Race Condition). CVSS score: 8.3/10. Published 2020-07-17.
How severe is CVE-2020-1645?: High severity. CVSS v3 base score is 8.3 out of 10.