CVE-2026-21911
published 2026-01-15CVE-2026-21911: An Incorrect Calculation vulnerability in the Layer 2 Control Protocol Daemon (l2cpd) of Juniper Networks Junos OS Evolved allows an unauthenticated…
PriorityP429medium6.5CVSS 3.1
AVAACLPRNUINSUCNINAH
EPSS
0.22%
13.2th percentile
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.
Affected
14 ranges
| Vendor | Product | Version range | Fixed in |
|---|---|---|---|
| juniper | junos_os | — | — |
| juniper | junos_os_evolved | < 21.4 | 21.4 |
| juniper | junos_os_evolved | — | — |
| juniper | junos_os_evolved | — | — |
| juniper | junos_os_evolved | — | — |
| juniper | junos_os_evolved | — | — |
| juniper | junos_os_evolved | — | — |
| juniper | junos_os_evolved | — | — |
| juniper_networks | junos_os_evolved | < 21.4R3-S7-EVO | 21.4R3-S7-EVO |
| juniper_networks | junos_os_evolved | >= 22.2 < 22.2R3-S4-EVO | 22.2R3-S4-EVO |
| juniper_networks | junos_os_evolved | >= 22.3 < 22.3R3-S3-EVO | 22.3R3-S3-EVO |
| juniper_networks | junos_os_evolved | >= 22.4 < 22.4R3-S2-EVO | 22.4R3-S2-EVO |
| juniper_networks | junos_os_evolved | >= 23.2 < 23.2R2-S1-EVO | 23.2R2-S1-EVO |
| juniper_networks | junos_os_evolved | >= 23.4 < 23.4R1-S2-EVO, 23.4R2-EVO | 23.4R1-S2-EVO, 23.4R2-EVO |
CVSS provenance
nvdv3.16.5MEDIUMCVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
nvdv4.07.1HIGHCVSS:4.0/AV:A/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:L/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:Y/R:A/V:C/RE:M/U:Amber
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Juniper
CVE-2026-21911: An Incorrect Calculation vulnerability in the Layer 2 Control
Protocol
Daemon (l2cpd) of Juniper Networks Junos OS Evolved allows an unauthenticat
vendor_juniper·2026-01-15·CVSS 6.5
CVE-2026-21911 [MEDIUM] CWE-682 CVE-2026-21911: An Incorrect Calculation vulnerability in the Layer 2 Control
Protocol
Daemon (l2cpd) of Juniper Networks Junos OS Evolved allows an unauthenticat
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
GHSA
GHSA-6fvr-r66p-5w4v: An Incorrect Calculation vulnerability in the Layer 2 Control
Protocol
Daemon (l2cpd) of Juniper Networks Junos OS Evolved allows an unauthenticated
ghsa_unreviewed·2026-01-15
CVE-2026-21911 [HIGH] CWE-682 GHSA-6fvr-r66p-5w4v: An Incorrect Calculation vulnerability in the Layer 2 Control
Protocol
Daemon (l2cpd) of Juniper Networks Junos OS Evolved allows an unauthenticated
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 progr
No detection rules found.
No public exploits indexed.
No writeups or analysis indexed.
2026-01-15
Published