CVE-2019-0048
EX4300 Series: When a firewall filter is applied to a loopback interface, other firewall filters for multicast traffic may fail
- 5.8MediumCVSS base score
- 0.97%Exploitation in 30 daysEPSS · top 38% of all CVEs
- NoKnown exploitednot in CISA's KEV catalog
- NonePublic exploitsnone known yet
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.
Timeline
ID reserved
By juniper
- 9 months later
· 9 months later
Published
- 5 years later
· 5 years later
Record updated
Changes after publication (a new score, a public exploit, EPSS crossing 1, 10 or 50 %, leaving KEV) are kept since November 2026; earlier ones are not known.
Scores
| Scored by | CVSS | Score | Vector |
|---|---|---|---|
| juniperCNA (assigner) | 3.0 | Medium5.8 | CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:C/C:N/I:L/A:N |
| NVDNVD · Modified | 3.1 | Medium5.8 | CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:N/I:L/A:N |
- EPSS (exploitation in 30 days)
- 0.97% · top 38% of all CVEs (11 Nov 2026)
The list uses the assigner's score when there is one, then CISA's, then NVD's: Medium 5.8.
Affected products
- affected 14.1X53 versions prior to 14.1X53-D51 and 14.1X53-D115 on EX4300 Series
- affected 17.1 versions prior to 17.1R3 on EX4300 Series
- affected 17.2 versions prior to 17.2R3-S2 on EX4300 Series
- affected 17.3 versions prior to 17.3R3-S3 on EX4300 Series
- affected 17.4 versions prior to 17.4R2-S5 and 17.4R3 on EX4300 Series
- affected 18.1 versions prior to 18.1R3-S1 on EX4300 Series
- affected 18.2 versions prior to 18.2R2 on EX4300 Series
- affected 18.3 versions prior to 18.3R2 on EX4300 Series
What to do
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.
Exploitation: Juniper SIRT is not aware of any malicious exploitation of this vulnerability.
References
References1
- https://kb.juniper.net/JSA10942 (opens in a new tab)x_refsource_CONFIRMx_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)
- EUVD EUVD-2019-0855 (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
[](https://cveledger.app/cve/CVE-2019-0048)Record last updated .