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Fencer Intel
medium 6.5

CVE-2018-0056 json

MX Series: L2ALD daemon may crash if a duplicate MAC is learned by two different interfaces

published 2018-10-10 8 y ago modified 2026-06-17 4 mo ago also EUVD-2018-0880

cvss
6.5
version 3.0, CNA
cisa kev
Not listed
not in CISA's catalog
epss
0.6%
EPSS 0.6% chance of exploitation in 30 days, percentile 49%
public exploits
0
none known

Summary

If a duplicate MAC address is learned by two different interfaces on an MX Series device, the MAC address learning function correctly flaps between the interfaces. However, the Layer 2 Address Learning Daemon (L2ALD) daemon might crash when attempting to delete the duplicate MAC address when the particular entry is not found in the internal MAC address table. This issue only occurs on MX Series devices with l2-backhaul VPN configured. No other products or platforms are affected by this issue. Affected releases are Juniper Networks Junos OS: 15.1 versions prior to 15.1R7-S1 on MX Series; 16.1 versions prior to 16.1R4-S12, 16.1R6-S6 on MX Series; 16.2 versions prior to 16.2R2-S7 on MX Series; 17.1 versions prior to 17.1R2-S9 on MX Series; 17.2 versions prior to 17.2R1-S7, 17.2R2-S6 on MX Series; 17.3 versions prior to 17.3R2-S4, 17.3R3-S1 on MX Series; 17.4 versions prior to 17.4R1-S5 on MX Series; 18.1 versions prior to 18.1R2 on MX Series.

Patch / fix

  • Juniper Networks Junos OS 15.1R7-S1, 16.1R4-S12, 16.1R6-S6, 16.2R2-S7, 17.1R2-S9, 17.2R1-S7, 17.2R2-S6, 17.3R2-S4, 17.3R3-S1, 17.4R1-S5, 18.1R2

Exploit prediction

0.61% chance of exploitation in the next 30 days, higher than 49% of all scored CVEs (FIRST EPSS, 2026-11-09).

CVSS scores

assigned by version score vector
CNA 3.0 6.5 CVSS:3.0/AV:A/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
NVD 3.0 5.3 CVSS:3.0/AV:A/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H
NVD 2.0 2.9 AV:A/AC:M/Au:N/C:N/I:N/A:P

Affected products

  • Juniper Networks Junos OS

Classification

Weakness
  • CWE-20 Improper Input Validation

References

Sources

Fencer Intel keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.