CVE-2026-21911

EUVD-2026-2699
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.
ProviderTypeBase ScoreAtk. VectorAtk. ComplexityPriv. RequiredVector
NISTPrimary
6.5 MEDIUM
ADJACENT_NETWORK
LOW
NONE
CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
juniperCNA
6.5 MEDIUM
ADJACENT_NETWORK
LOW
NONE
CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
Base Score
CVSS 3.x
EPSS Score
Percentile: Unknown
Affected Products (NVD)
VendorProductVersion
juniperjunos_os_evolved
𝑥
< 21.4
juniperjunos_os_evolved
21.4
juniperjunos_os_evolved
21.4:r1
juniperjunos_os_evolved
21.4:r1-s1
juniperjunos_os_evolved
21.4:r1-s2
juniperjunos_os_evolved
21.4:r2
juniperjunos_os_evolved
21.4:r2-s1
juniperjunos_os_evolved
21.4:r2-s2
juniperjunos_os_evolved
21.4:r3
juniperjunos_os_evolved
21.4:r3-s1
juniperjunos_os_evolved
21.4:r3-s2
juniperjunos_os_evolved
21.4:r3-s3
juniperjunos_os_evolved
21.4:r3-s4
juniperjunos_os_evolved
21.4:r3-s5
juniperjunos_os_evolved
21.4:r3-s6
juniperjunos_os_evolved
22.2
juniperjunos_os_evolved
22.2:r1
juniperjunos_os_evolved
22.2:r1-s1
juniperjunos_os_evolved
22.2:r1-s2
juniperjunos_os_evolved
22.2:r2
juniperjunos_os_evolved
22.2:r2-s1
juniperjunos_os_evolved
22.2:r2-s2
juniperjunos_os_evolved
22.2:r3
juniperjunos_os_evolved
22.2:r3-s1
juniperjunos_os_evolved
22.2:r3-s2
juniperjunos_os_evolved
22.2:r3-s3
juniperjunos_os_evolved
22.3
juniperjunos_os_evolved
22.3:r1
juniperjunos_os_evolved
22.3:r1-s1
juniperjunos_os_evolved
22.3:r1-s2
juniperjunos_os_evolved
22.3:r2
juniperjunos_os_evolved
22.3:r2-s1
juniperjunos_os_evolved
22.3:r2-s2
juniperjunos_os_evolved
22.3:r3
juniperjunos_os_evolved
22.3:r3-s1
juniperjunos_os_evolved
22.3:r3-s2
juniperjunos_os_evolved
22.4
juniperjunos_os_evolved
22.4:r1
juniperjunos_os_evolved
22.4:r1-s1
juniperjunos_os_evolved
22.4:r1-s2
juniperjunos_os_evolved
22.4:r2
juniperjunos_os_evolved
22.4:r2-s1
juniperjunos_os_evolved
22.4:r2-s2
juniperjunos_os_evolved
22.4:r3
juniperjunos_os_evolved
22.4:r3-s1
juniperjunos_os_evolved
23.2
juniperjunos_os_evolved
23.2:r1
juniperjunos_os_evolved
23.2:r1-s1
juniperjunos_os_evolved
23.2:r1-s2
juniperjunos_os_evolved
23.2:r2
juniperjunos_os_evolved
23.4
juniperjunos_os_evolved
23.4:r1
juniperjunos_os_evolved
23.4:r1-s1
juniperjunos_os_evolved
23.4:r2
𝑥
= Vulnerable software versions