CVE-2019-0048

EX4300 Series: When a firewall filter is applied to a loopback interface, other firewall filters for multicast traffic may fail

Description

On EX4300 Series switches with TCAM optimization enabled, incoming multicast traffic matches an implicit loopback filter rule first, since it has high priority. This rule is meant for reserved multicast addresses 224.0.0.x, but incorrectly matches on 224.x.x.x. Due to this bug, when a firewall filter is applied on the loopback interface, other firewall filters might stop working for multicast traffic. The command 'show firewall filter' can be used to confirm whether the filter is working. This issue only affects the EX4300 switch. No other products or platforms are affected by this vulnerability. This issue affects: Juniper Networks Junos OS: 14.1X53 versions prior to 14.1X53-D51, 14.1X53-D115 on EX4300 Series; 17.1 versions prior to 17.1R3 on EX4300 Series; 17.2 versions prior to 17.2R3-S2 on EX4300 Series; 17.3 versions prior to 17.3R3-S3 on EX4300 Series; 17.4 versions prior to 17.4R2-S5, 17.4R3 on EX4300 Series; 18.1 versions prior to 18.1R3-S1 on EX4300 Series; 18.2 versions prior to 18.2R2 on EX4300 Series; 18.3 versions prior to 18.3R2 on EX4300 Series.

Remediation

Solution:

  • The following software releases have been updated to resolve this specific issue: 14.1X53-D51, 14.1X53-D115, 17.1R3, 17.2R3-S2, 17.3R3-S3, 17.4R2-S5, 17.4R3, 18.1R3-S1, 18.2R2, 18.3R2, 18.4R1, and all subsequent releases.

Workaround:

  • Disabling TCAM optimization will mitigate this issue.

Category

5.8
CVSS
Severity: Medium
CVSS 3.1 •
CVSS 3.0 •
CVSS 2.0 •
EPSS 0.21%
Vendor Advisory juniper.net
Affected: Juniper Networks Junos OS
Published at:
Updated at:

References

Link Tags
https://kb.juniper.net/JSA10942 patch vendor advisory

Frequently Asked Questions

What is the severity of CVE-2019-0048?
CVE-2019-0048 has been scored as a medium severity vulnerability.
How to fix CVE-2019-0048?
To fix CVE-2019-0048: The following software releases have been updated to resolve this specific issue: 14.1X53-D51, 14.1X53-D115, 17.1R3, 17.2R3-S2, 17.3R3-S3, 17.4R2-S5, 17.4R3, 18.1R3-S1, 18.2R2, 18.3R2, 18.4R1, and all subsequent releases.
Is CVE-2019-0048 being actively exploited in the wild?
As for now, there are no information to confirm that CVE-2019-0048 is being actively exploited. According to its EPSS score, there is a ~0% probability that this vulnerability will be exploited by malicious actors in the next 30 days.
What software or system is affected by CVE-2019-0048?
CVE-2019-0048 affects Juniper Networks Junos OS.
This platform uses data from the NIST NVD, MITRE CVE, MITRE CWE, First.org and CISA KEV but is not endorsed or certified by these entities. CVE is a registred trademark of the MITRE Corporation and the authoritative source of CVE content is MITRE's CVE web site. CWE is a registred trademark of the MITRE Corporation and the authoritative source of CWE content is MITRE's CWE web site.
© 2025 Under My Watch. All Rights Reserved.