Vulnerability Database

320,453

Total vulnerabilities in the database

CVE-2026-21911

An Incorrect Calculation vulnerability in the Layer 2 Control

Protocol

Daemon (l2cpd) of Juniper Networks Junos OS Evolved allows an unauthenticated network-adjacent attacker flapping the management interface to cause the learning of new MACs over label-switched interfaces (LSI) to stop while generating a flood of logs, resulting in high CPU usage.

When the issue is seen, the following log message will be generated:

op:1 flag:0x6 mac:xx:xx:xx:xx:xx:xx bd:2 ifl:13302 reason:0(REASON_NONE) i-op:6(INTRNL_OP_HW_FORCE_DELETE) status:10 lstatus:10 err:26(GETIFBD_VALIDATE_FAILED) err-reason 4(IFBD_VALIDATE_FAIL_EPOCH_MISMATCH) hw_wr:0x4 ctxsync:0 fwdsync:0 rtt-id:51 p_ifl:0 fwd_nh:0 svlbnh:0 event:- smask:0x100000000 dmask:0x0 mplsmask 0x1 act:0x5800 extf:0x0 pfe-id 0 hw-notif-ifl 13302 programmed-ifl 4294967295 pseudo-vtep underlay-ifl-idx 0 stack:GET_MAC, ALLOCATE_MAC, GET_IFL, GET_IFF, GET_IFBD, STOP,

This issue affects Junos OS Evolved: 

  • all versions before 21.4R3-S7-EVO, 
  • from 22.2 before 22.2R3-S4-EVO, 
  • from 22.3 before 22.3R3-S3-EVO, 
  • from 22.4 before 22.4R3-S2-EVO, 
  • from 23.2 before 23.2R2-S1-EVO, 
  • from 23.4 before 23.4R1-S2-EVO, 23.4R2-EVO.
  • Published: Jan 15, 2026
  • Updated: Jan 16, 2026
  • CVE: CVE-2026-21911
  • Severity: Medium
  • Exploit:

CVSS v3:

  • Severity: Medium
  • Score: 6.5
  • AV:A/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

CWEs:

Software From Fixed in
juniper / junos_os_evolved - 21.4
juniper / junos_os_evolved 21.4 21.4.x
juniper / junos_os_evolved 21.4-r1 21.4-r1.x
juniper / junos_os_evolved 21.4-r1-s1 21.4-r1-s1.x
juniper / junos_os_evolved 21.4-r1-s2 21.4-r1-s2.x
juniper / junos_os_evolved 21.4-r2 21.4-r2.x
juniper / junos_os_evolved 21.4-r2-s1 21.4-r2-s1.x
juniper / junos_os_evolved 21.4-r2-s2 21.4-r2-s2.x
juniper / junos_os_evolved 21.4-r3 21.4-r3.x
juniper / junos_os_evolved 21.4-r3-s1 21.4-r3-s1.x
juniper / junos_os_evolved 21.4-r3-s2 21.4-r3-s2.x
juniper / junos_os_evolved 21.4-r3-s3 21.4-r3-s3.x
juniper / junos_os_evolved 21.4-r3-s4 21.4-r3-s4.x
juniper / junos_os_evolved 21.4-r3-s5 21.4-r3-s5.x
juniper / junos_os_evolved 21.4-r3-s6 21.4-r3-s6.x
juniper / junos_os_evolved 22.2 22.2.x
juniper / junos_os_evolved 22.2-r1 22.2-r1.x
juniper / junos_os_evolved 22.2-r1-s1 22.2-r1-s1.x
juniper / junos_os_evolved 22.2-r1-s2 22.2-r1-s2.x
juniper / junos_os_evolved 22.2-r2 22.2-r2.x
juniper / junos_os_evolved 22.2-r2-s1 22.2-r2-s1.x
juniper / junos_os_evolved 22.2-r2-s2 22.2-r2-s2.x
juniper / junos_os_evolved 22.2-r3 22.2-r3.x
juniper / junos_os_evolved 22.2-r3-s1 22.2-r3-s1.x
juniper / junos_os_evolved 22.2-r3-s2 22.2-r3-s2.x
juniper / junos_os_evolved 22.2-r3-s3 22.2-r3-s3.x
juniper / junos_os_evolved 22.3 22.3.x
juniper / junos_os_evolved 22.3-r1 22.3-r1.x
juniper / junos_os_evolved 22.3-r1-s1 22.3-r1-s1.x
juniper / junos_os_evolved 22.3-r1-s2 22.3-r1-s2.x
juniper / junos_os_evolved 22.3-r2 22.3-r2.x
juniper / junos_os_evolved 22.3-r2-s1 22.3-r2-s1.x
juniper / junos_os_evolved 22.3-r2-s2 22.3-r2-s2.x
juniper / junos_os_evolved 22.3-r3 22.3-r3.x
juniper / junos_os_evolved 22.3-r3-s1 22.3-r3-s1.x
juniper / junos_os_evolved 22.3-r3-s2 22.3-r3-s2.x
juniper / junos_os_evolved 22.4 22.4.x
juniper / junos_os_evolved 22.4-r1 22.4-r1.x
juniper / junos_os_evolved 22.4-r1-s1 22.4-r1-s1.x
juniper / junos_os_evolved 22.4-r1-s2 22.4-r1-s2.x
juniper / junos_os_evolved 22.4-r2 22.4-r2.x
juniper / junos_os_evolved 22.4-r2-s1 22.4-r2-s1.x
juniper / junos_os_evolved 22.4-r2-s2 22.4-r2-s2.x
juniper / junos_os_evolved 22.4-r3 22.4-r3.x
juniper / junos_os_evolved 22.4-r3-s1 22.4-r3-s1.x
juniper / junos_os_evolved 23.2 23.2.x
juniper / junos_os_evolved 23.2-r1 23.2-r1.x
juniper / junos_os_evolved 23.2-r1-s1 23.2-r1-s1.x
juniper / junos_os_evolved 23.2-r1-s2 23.2-r1-s2.x
juniper / junos_os_evolved 23.2-r2 23.2-r2.x
juniper / junos_os_evolved 23.4 23.4.x
juniper / junos_os_evolved 23.4-r1 23.4-r1.x
juniper / junos_os_evolved 23.4-r1-s1 23.4-r1-s1.x
juniper / junos_os_evolved 23.4-r2 23.4-r2.x