When the "Intrusion Detection Service" (IDS) feature is configured on Juniper Networks MX series with a dynamic firewall filter using IPv6 source or destination prefix, it may incorrectly match the prefix as /32, causing the filter to block unexpected traffic. This issue affects only IPv6 prefixes when used as source and destination. This issue affects MX Series devices using MS-MPC, MS-MIC or MS-SPC3 service cards with IDS service configured. This issue affects: Juniper Networks Junos OS 17.3 versions prior to 17.3R3-S10 on MX Series.

17.4 versions prior to 17.4R3-S3 on MX Series.

18.1 versions prior to 18.1R3-S11 on MX Series.

18.2 versions prior to 18.2R3-S6 on MX Series.

18.3 versions prior to 18.3R3-S4 on MX Series.

18.4 versions prior to 18.4R3-S6 on MX Series.

19.1 versions prior to 19.1R2-S2, 19.1R3-S3 on MX Series.

19.2 versions prior to 19.2R3-S1 on MX Series.

19.3 versions prior to 19.3R2-S5, 19.3R3-S1 on MX Series.

19.4 versions prior to 19.4R3 on MX Series.

20.1 versions prior to 20.1R2 on MX Series.

20.2 versions prior to 20.2R2 on MX Series;.