NVD

CVE-2026-21911 Detail

Description

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.

Metrics

NVD enrichment efforts reference publicly available information to associate vector strings. CVSS information contributed by other sources is also displayed.

CVSS 4.0 Severity and Vector Strings:

NIST: NVD

N/A

NVD assessment not yet provided.

Nist CVSS score does not match with CNA score

CNA: Juniper Networks, Inc.

CVSS-B 7.1 HIGH

Vector: CVSS:4.0/AV:A/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:L/AU:Y/R:A/V:C/RE:M/U:Amber

CVSS 3.x Severity and Vector Strings:

CNA: Juniper Networks, Inc.

Base Score: 6.5 MEDIUM

Vector: CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

CVSS 2.0 Severity and Vector Strings:

National Institute of Standards and Technology

NIST: NVD

Base Score: N/A

NVD assessment not yet provided.

References to Advisories, Solutions, and Tools

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URL	Source(s)	Tag(s)
https://kb.juniper.net/JSA106010	Juniper Networks, Inc.	Vendor Advisory
https://supportportal.juniper.net/JSA106010	Juniper Networks, Inc.	Vendor Advisory

Weakness Enumeration

CWE-ID	CWE Name	Source
CWE-682	Incorrect Calculation	Juniper Networks, Inc.

Known Affected Software Configurations Switch to CPE 2.2

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Change History

2 change records found show changes

Initial Analysis by NIST 1/23/2026 11:59:03 AM

Action

Type

Old Value

New Value

Added

CPE Configuration

Record truncated, showing 2048 of 3681 characters.
View Entire Change Record

OR
          *cpe:2.3:o:juniper:junos_os_evolved:21.4:r1:*:*:*:*:*:*
          *cpe:2.3:o:juniper:junos_os_evolved:21.4:r1-s1:*:*:*:*:*:*
          *cpe:2.3:o:juniper:junos_os_evolved:21.4:-:*:*:*:*:*:*
          *cpe:2.3:o:juniper:junos_os_evolved:21.4:r2:*:*:*:*:*:*
          *cpe:2.3:o:juniper:junos_os_evolved:21.4:r2-s1:*:*:*:*:*:*
          *cpe:2.3:o:juniper:junos_os_evolved:21.4:r2-s2:*:*:*:*:*:*
          *cpe:2.3:o:juniper:junos_os_evolved:21.4:r1-s2:*:*:*:*:*:*
          *cpe:2.3:o:juniper:junos_os_evolved:22.2:r1-s1:*:*:*:*:*:*
          *cpe:2.3:o:juniper:junos_os_evolved:22.2:r1:*:*:*:*:*:*
          *cpe:2.3:o:juniper:junos_os_evolved:22.3:r1:*:*:*:*:*:*
          *cpe:2.3:o:juniper:junos_os_evolved:21.4:r3:*:*:*:*:*:*
          *cpe:2.3:o:juniper:junos_os_evolved:22.2:r2:*:*:*:*:*:*
          *cpe:2.3:o:juniper:junos_os_evolved:21.4:r3-s1:*:*:*:*:*:*
          *cpe:2.3:o:juniper:junos_os_evolved:21.4:r3-s2:*:*:*:*:*:*
          *cpe:2.3:o:juniper:junos_os_evolved:21.4:r3-s3:*:*:*:*:*:*
          *cpe:2.3:o:juniper:junos_os_evolved:22.2:r2-s1:*:*:*:*:*:*
          *cpe:2.3:o:juniper:junos_os_evolved:22.2:r2-s2:*:*:*:*:*:*
          *cpe:2.3:o:juniper:junos_os_evolved:22.2:r3:*:*:*:*:*:*
          *cpe:2.3:o:juniper:junos_os_evolved:22.3:r1-s1:*:*:*:*:*:*
          *cpe:2.3:o:juniper:junos_os_evolved:22.3:r1-s2:*:*:*:*:*:*
          *cpe:2.3:o:juniper:junos_os_evolved:22.3:r2:*:*:*:*:*:*
          *cpe:2.3:o:juniper:junos_os_evolved:22.4:r1:*:*:*:*:*:*
          *cpe:2.3:o:juniper:junos_os_evolved:22.4:r1-s1:*:*:*:*:*:*
          *cpe:2.3:o:juniper:junos_os_evolved:22.4:r1-s2:*:*:*:*:*:*
          *cpe:2.3:o:juniper:junos_os_evolved:22.4:r2:*:*:*:*:*:*
          *cpe:2.3:o:juniper:junos_os_evolved:22.3:r2-s1:*:*:*:*:*:*
          *cpe:2.3:o:juniper:junos_os_evolved:22.2:r3-s1:*:*:*:*:*:*
          *cpe:2.3:o:juniper:junos_os_evolved:23.2:-:*:*:*:*:*:*
          *cpe:2.3:o:juniper:junos_os_evolved:23.2:r1:*:*:*:*:*:*
          *cpe:2.3:o:juniper:junos_os_evolved:23.2:r1-s1:*:*:*:*:*:*
          *cpe:2

Added

Reference Type

Juniper Networks, Inc.: https://kb.juniper.net/JSA106010 Types: Vendor Advisory

Added

Reference Type

Juniper Networks, Inc.: https://supportportal.juniper.net/JSA106010 Types: Vendor Advisory

New CVE Received from Juniper Networks, Inc. 1/15/2026 4:16:07 PM

Action	Type	New Value
Added	Description	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.
Added	CVSS V4.0	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
Added	CVSS V3.1	AV:A/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
Added	CWE	CWE-682
Added	Reference	https://kb.juniper.net/JSA106010
Added	Reference	https://supportportal.juniper.net/JSA106010

Quick Info

CVE Dictionary Entry:
CVE-2026-21911
NVD Published Date:
01/15/2026
NVD Last Modified:
01/23/2026
Source:
Juniper Networks, Inc.

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Information Technology Laboratory

National Vulnerability Database

National Vulnerability Database

CVE-2026-21911 Detail

Description

Metrics

References to Advisories, Solutions, and Tools

Weakness Enumeration

Known Affected Software Configurations Switch to CPE 2.2

CPEs loading, please wait.

Change History

Initial Analysis by NIST 1/23/2026 11:59:03 AM

New CVE Received from Juniper Networks, Inc. 1/15/2026 4:16:07 PM

Quick Info