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TI-2026-17611 Aliases CVE-2026-21911GHSA-6fvr-r66p-5w4v

Junos OS Evolved: Flapping management interface causes MAC learning on label-switched interfaces to stop

Priority LOW 31CWE-682Published · Updated

Key facts

Attack vector
Adjacent network
Privileges required
None
User interaction
None
Attack complexity
Low
Attack requirements
None
Impact type
—
Confidentiality · integrity · availability
None · None · High
Fix status
Fixed

Attack profile from CVSS 4.0 · CNA. Fix status from CNA.

Summary

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.

Why it matters now

Exploitation None reported CISA SSVC · not in CISA KEV
EPSS 0.00239 14th percentileScored 2026-11-07
Fix Fixed Junos OS Evolved (Juniper Networks): 21.4R3-S7-EVO, 22.2R3-S4-EVO, 22.3R3-S3-EVO +4

SSVC decision points

CISA ADP · SSVC 2.0.3

Exploitation
None
Automatable
No
Technical impact
Partial

The decision (Track, Attend, Act) also depends on your mission and well-being impact; see CISA's SSVC guide.

Affected products

VendorProductAffected versionsFixed inStatusSource
JuniperJunos OS Evolvedbefore 21.4R3-S7-EVO; 22.2 to before 22.2R3-S4-EVO; 22.3 to before 22.3R3-S3-EVO; 22.4 to before 22.4R3-S2-EVO; 23.2 to before 23.2R2-S1-EVO; 23.4 to before 23.4R1-S2-EVO, 23.4R2-EVO21.4R3-S7-EVO, 22.2R3-S4-EVO, 22.3R3-S3-EVO, 22.4R3-S2-EVO, 23.2R2-S1-EVO, 23.4R1-S2-EVO, 23.4R2-EVOPatch availableCNA
  • Junos OS Evolved VendorJuniper Affected before 21.4R3-S7-EVO; 22.2 to before 22.2R3-S4-EVO; 22.3 to before 22.3R3-S3-EVO; 22.4 to before 22.4R3-S2-EVO; 23.2 to before 23.2R2-S1-EVO; 23.4 to before 23.4R1-S2-EVO, 23.4R2-EVO Fixed in 21.4R3-S7-EVO, 22.2R3-S4-EVO, 22.3R3-S3-EVO, 22.4R3-S2-EVO, 23.2R2-S1-EVO, 23.4R1-S2-EVO, 23.4R2-EVO Patch available CNA

CPE configurations NVD · 54

CPEVersionsRoleVendor
cpe:2.3:o:juniper:junos_os_evolved:*:*:*:*:*:*:*:*before 21.4VulnerableJuniper
cpe:2.3:o:juniper:junos_os_evolved:21.4:-:*:*:*:*:*:*21.4VulnerableJuniper
cpe:2.3:o:juniper:junos_os_evolved:21.4:r1:*:*:*:*:*:*21.4 r1VulnerableJuniper
cpe:2.3:o:juniper:junos_os_evolved:21.4:r1-s1:*:*:*:*:*:*21.4 r1-s1VulnerableJuniper
cpe:2.3:o:juniper:junos_os_evolved:21.4:r1-s2:*:*:*:*:*:*21.4 r1-s2VulnerableJuniper
cpe:2.3:o:juniper:junos_os_evolved:21.4:r2:*:*:*:*:*:*21.4 r2VulnerableJuniper
cpe:2.3:o:juniper:junos_os_evolved:21.4:r2-s1:*:*:*:*:*:*21.4 r2-s1VulnerableJuniper
cpe:2.3:o:juniper:junos_os_evolved:21.4:r2-s2:*:*:*:*:*:*21.4 r2-s2VulnerableJuniper
cpe:2.3:o:juniper:junos_os_evolved:21.4:r3:*:*:*:*:*:*21.4 r3VulnerableJuniper
cpe:2.3:o:juniper:junos_os_evolved:21.4:r3-s1:*:*:*:*:*:*21.4 r3-s1VulnerableJuniper
  • cpe:2.3:o:juniper:junos_os_evolved:*:*:*:*:*:*:*:* Versions before 21.4 Vulnerable ·Juniper
  • cpe:2.3:o:juniper:junos_os_evolved:21.4:-:*:*:*:*:*:* Versions 21.4 Vulnerable ·Juniper
  • cpe:2.3:o:juniper:junos_os_evolved:21.4:r1:*:*:*:*:*:* Versions 21.4 r1 Vulnerable ·Juniper
  • cpe:2.3:o:juniper:junos_os_evolved:21.4:r1-s1:*:*:*:*:*:* Versions 21.4 r1-s1 Vulnerable ·Juniper
  • cpe:2.3:o:juniper:junos_os_evolved:21.4:r1-s2:*:*:*:*:*:* Versions 21.4 r1-s2 Vulnerable ·Juniper
  • cpe:2.3:o:juniper:junos_os_evolved:21.4:r2:*:*:*:*:*:* Versions 21.4 r2 Vulnerable ·Juniper
  • cpe:2.3:o:juniper:junos_os_evolved:21.4:r2-s1:*:*:*:*:*:* Versions 21.4 r2-s1 Vulnerable ·Juniper
  • cpe:2.3:o:juniper:junos_os_evolved:21.4:r2-s2:*:*:*:*:*:* Versions 21.4 r2-s2 Vulnerable ·Juniper
  • cpe:2.3:o:juniper:junos_os_evolved:21.4:r3:*:*:*:*:*:* Versions 21.4 r3 Vulnerable ·Juniper
  • cpe:2.3:o:juniper:junos_os_evolved:21.4:r3-s1:*:*:*:*:*:* Versions 21.4 r3-s1 Vulnerable ·Juniper
Show 44 more CPE
CPEVersionsRoleVendor
cpe:2.3:o:juniper:junos_os_evolved:21.4:r3-s2:*:*:*:*:*:*21.4 r3-s2VulnerableJuniper
cpe:2.3:o:juniper:junos_os_evolved:21.4:r3-s3:*:*:*:*:*:*21.4 r3-s3VulnerableJuniper
cpe:2.3:o:juniper:junos_os_evolved:21.4:r3-s4:*:*:*:*:*:*21.4 r3-s4VulnerableJuniper
cpe:2.3:o:juniper:junos_os_evolved:21.4:r3-s5:*:*:*:*:*:*21.4 r3-s5VulnerableJuniper
cpe:2.3:o:juniper:junos_os_evolved:21.4:r3-s6:*:*:*:*:*:*21.4 r3-s6VulnerableJuniper
cpe:2.3:o:juniper:junos_os_evolved:22.2:-:*:*:*:*:*:*22.2VulnerableJuniper
cpe:2.3:o:juniper:junos_os_evolved:22.2:r1:*:*:*:*:*:*22.2 r1VulnerableJuniper
cpe:2.3:o:juniper:junos_os_evolved:22.2:r1-s1:*:*:*:*:*:*22.2 r1-s1VulnerableJuniper
cpe:2.3:o:juniper:junos_os_evolved:22.2:r1-s2:*:*:*:*:*:*22.2 r1-s2VulnerableJuniper
cpe:2.3:o:juniper:junos_os_evolved:22.2:r2:*:*:*:*:*:*22.2 r2VulnerableJuniper
cpe:2.3:o:juniper:junos_os_evolved:22.2:r2-s1:*:*:*:*:*:*22.2 r2-s1VulnerableJuniper
cpe:2.3:o:juniper:junos_os_evolved:22.2:r2-s2:*:*:*:*:*:*22.2 r2-s2VulnerableJuniper
cpe:2.3:o:juniper:junos_os_evolved:22.2:r3:*:*:*:*:*:*22.2 r3VulnerableJuniper
cpe:2.3:o:juniper:junos_os_evolved:22.2:r3-s1:*:*:*:*:*:*22.2 r3-s1VulnerableJuniper
cpe:2.3:o:juniper:junos_os_evolved:22.2:r3-s2:*:*:*:*:*:*22.2 r3-s2VulnerableJuniper
cpe:2.3:o:juniper:junos_os_evolved:22.2:r3-s3:*:*:*:*:*:*22.2 r3-s3VulnerableJuniper
cpe:2.3:o:juniper:junos_os_evolved:22.3:-:*:*:*:*:*:*22.3VulnerableJuniper
cpe:2.3:o:juniper:junos_os_evolved:22.3:r1:*:*:*:*:*:*22.3 r1VulnerableJuniper
cpe:2.3:o:juniper:junos_os_evolved:22.3:r1-s1:*:*:*:*:*:*22.3 r1-s1VulnerableJuniper
cpe:2.3:o:juniper:junos_os_evolved:22.3:r1-s2:*:*:*:*:*:*22.3 r1-s2VulnerableJuniper
cpe:2.3:o:juniper:junos_os_evolved:22.3:r2:*:*:*:*:*:*22.3 r2VulnerableJuniper
cpe:2.3:o:juniper:junos_os_evolved:22.3:r2-s1:*:*:*:*:*:*22.3 r2-s1VulnerableJuniper
cpe:2.3:o:juniper:junos_os_evolved:22.3:r2-s2:*:*:*:*:*:*22.3 r2-s2VulnerableJuniper
cpe:2.3:o:juniper:junos_os_evolved:22.3:r3:*:*:*:*:*:*22.3 r3VulnerableJuniper
cpe:2.3:o:juniper:junos_os_evolved:22.3:r3-s1:*:*:*:*:*:*22.3 r3-s1VulnerableJuniper
cpe:2.3:o:juniper:junos_os_evolved:22.3:r3-s2:*:*:*:*:*:*22.3 r3-s2VulnerableJuniper
cpe:2.3:o:juniper:junos_os_evolved:22.4:-:*:*:*:*:*:*22.4VulnerableJuniper
cpe:2.3:o:juniper:junos_os_evolved:22.4:r1:*:*:*:*:*:*22.4 r1VulnerableJuniper
cpe:2.3:o:juniper:junos_os_evolved:22.4:r1-s1:*:*:*:*:*:*22.4 r1-s1VulnerableJuniper
cpe:2.3:o:juniper:junos_os_evolved:22.4:r1-s2:*:*:*:*:*:*22.4 r1-s2VulnerableJuniper
cpe:2.3:o:juniper:junos_os_evolved:22.4:r2:*:*:*:*:*:*22.4 r2VulnerableJuniper
cpe:2.3:o:juniper:junos_os_evolved:22.4:r2-s1:*:*:*:*:*:*22.4 r2-s1VulnerableJuniper
cpe:2.3:o:juniper:junos_os_evolved:22.4:r2-s2:*:*:*:*:*:*22.4 r2-s2VulnerableJuniper
cpe:2.3:o:juniper:junos_os_evolved:22.4:r3:*:*:*:*:*:*22.4 r3VulnerableJuniper
cpe:2.3:o:juniper:junos_os_evolved:22.4:r3-s1:*:*:*:*:*:*22.4 r3-s1VulnerableJuniper
cpe:2.3:o:juniper:junos_os_evolved:23.2:-:*:*:*:*:*:*23.2VulnerableJuniper
cpe:2.3:o:juniper:junos_os_evolved:23.2:r1:*:*:*:*:*:*23.2 r1VulnerableJuniper
cpe:2.3:o:juniper:junos_os_evolved:23.2:r1-s1:*:*:*:*:*:*23.2 r1-s1VulnerableJuniper
cpe:2.3:o:juniper:junos_os_evolved:23.2:r1-s2:*:*:*:*:*:*23.2 r1-s2VulnerableJuniper
cpe:2.3:o:juniper:junos_os_evolved:23.2:r2:*:*:*:*:*:*23.2 r2VulnerableJuniper
cpe:2.3:o:juniper:junos_os_evolved:23.4:-:*:*:*:*:*:*23.4VulnerableJuniper
cpe:2.3:o:juniper:junos_os_evolved:23.4:r1:*:*:*:*:*:*23.4 r1VulnerableJuniper
cpe:2.3:o:juniper:junos_os_evolved:23.4:r1-s1:*:*:*:*:*:*23.4 r1-s1VulnerableJuniper
cpe:2.3:o:juniper:junos_os_evolved:23.4:r2:*:*:*:*:*:*23.4 r2VulnerableJuniper
  • cpe:2.3:o:juniper:junos_os_evolved:21.4:r3-s2:*:*:*:*:*:* Versions 21.4 r3-s2 Vulnerable ·Juniper
  • cpe:2.3:o:juniper:junos_os_evolved:21.4:r3-s3:*:*:*:*:*:* Versions 21.4 r3-s3 Vulnerable ·Juniper
  • cpe:2.3:o:juniper:junos_os_evolved:21.4:r3-s4:*:*:*:*:*:* Versions 21.4 r3-s4 Vulnerable ·Juniper
  • cpe:2.3:o:juniper:junos_os_evolved:21.4:r3-s5:*:*:*:*:*:* Versions 21.4 r3-s5 Vulnerable ·Juniper
  • cpe:2.3:o:juniper:junos_os_evolved:21.4:r3-s6:*:*:*:*:*:* Versions 21.4 r3-s6 Vulnerable ·Juniper
  • cpe:2.3:o:juniper:junos_os_evolved:22.2:-:*:*:*:*:*:* Versions 22.2 Vulnerable ·Juniper
  • cpe:2.3:o:juniper:junos_os_evolved:22.2:r1:*:*:*:*:*:* Versions 22.2 r1 Vulnerable ·Juniper
  • cpe:2.3:o:juniper:junos_os_evolved:22.2:r1-s1:*:*:*:*:*:* Versions 22.2 r1-s1 Vulnerable ·Juniper
  • cpe:2.3:o:juniper:junos_os_evolved:22.2:r1-s2:*:*:*:*:*:* Versions 22.2 r1-s2 Vulnerable ·Juniper
  • cpe:2.3:o:juniper:junos_os_evolved:22.2:r2:*:*:*:*:*:* Versions 22.2 r2 Vulnerable ·Juniper
  • cpe:2.3:o:juniper:junos_os_evolved:22.2:r2-s1:*:*:*:*:*:* Versions 22.2 r2-s1 Vulnerable ·Juniper
  • cpe:2.3:o:juniper:junos_os_evolved:22.2:r2-s2:*:*:*:*:*:* Versions 22.2 r2-s2 Vulnerable ·Juniper
  • cpe:2.3:o:juniper:junos_os_evolved:22.2:r3:*:*:*:*:*:* Versions 22.2 r3 Vulnerable ·Juniper
  • cpe:2.3:o:juniper:junos_os_evolved:22.2:r3-s1:*:*:*:*:*:* Versions 22.2 r3-s1 Vulnerable ·Juniper
  • cpe:2.3:o:juniper:junos_os_evolved:22.2:r3-s2:*:*:*:*:*:* Versions 22.2 r3-s2 Vulnerable ·Juniper
  • cpe:2.3:o:juniper:junos_os_evolved:22.2:r3-s3:*:*:*:*:*:* Versions 22.2 r3-s3 Vulnerable ·Juniper
  • cpe:2.3:o:juniper:junos_os_evolved:22.3:-:*:*:*:*:*:* Versions 22.3 Vulnerable ·Juniper
  • cpe:2.3:o:juniper:junos_os_evolved:22.3:r1:*:*:*:*:*:* Versions 22.3 r1 Vulnerable ·Juniper
  • cpe:2.3:o:juniper:junos_os_evolved:22.3:r1-s1:*:*:*:*:*:* Versions 22.3 r1-s1 Vulnerable ·Juniper
  • cpe:2.3:o:juniper:junos_os_evolved:22.3:r1-s2:*:*:*:*:*:* Versions 22.3 r1-s2 Vulnerable ·Juniper
  • cpe:2.3:o:juniper:junos_os_evolved:22.3:r2:*:*:*:*:*:* Versions 22.3 r2 Vulnerable ·Juniper
  • cpe:2.3:o:juniper:junos_os_evolved:22.3:r2-s1:*:*:*:*:*:* Versions 22.3 r2-s1 Vulnerable ·Juniper
  • cpe:2.3:o:juniper:junos_os_evolved:22.3:r2-s2:*:*:*:*:*:* Versions 22.3 r2-s2 Vulnerable ·Juniper
  • cpe:2.3:o:juniper:junos_os_evolved:22.3:r3:*:*:*:*:*:* Versions 22.3 r3 Vulnerable ·Juniper
  • cpe:2.3:o:juniper:junos_os_evolved:22.3:r3-s1:*:*:*:*:*:* Versions 22.3 r3-s1 Vulnerable ·Juniper
  • cpe:2.3:o:juniper:junos_os_evolved:22.3:r3-s2:*:*:*:*:*:* Versions 22.3 r3-s2 Vulnerable ·Juniper
  • cpe:2.3:o:juniper:junos_os_evolved:22.4:-:*:*:*:*:*:* Versions 22.4 Vulnerable ·Juniper
  • cpe:2.3:o:juniper:junos_os_evolved:22.4:r1:*:*:*:*:*:* Versions 22.4 r1 Vulnerable ·Juniper
  • cpe:2.3:o:juniper:junos_os_evolved:22.4:r1-s1:*:*:*:*:*:* Versions 22.4 r1-s1 Vulnerable ·Juniper
  • cpe:2.3:o:juniper:junos_os_evolved:22.4:r1-s2:*:*:*:*:*:* Versions 22.4 r1-s2 Vulnerable ·Juniper
  • cpe:2.3:o:juniper:junos_os_evolved:22.4:r2:*:*:*:*:*:* Versions 22.4 r2 Vulnerable ·Juniper
  • cpe:2.3:o:juniper:junos_os_evolved:22.4:r2-s1:*:*:*:*:*:* Versions 22.4 r2-s1 Vulnerable ·Juniper
  • cpe:2.3:o:juniper:junos_os_evolved:22.4:r2-s2:*:*:*:*:*:* Versions 22.4 r2-s2 Vulnerable ·Juniper
  • cpe:2.3:o:juniper:junos_os_evolved:22.4:r3:*:*:*:*:*:* Versions 22.4 r3 Vulnerable ·Juniper
  • cpe:2.3:o:juniper:junos_os_evolved:22.4:r3-s1:*:*:*:*:*:* Versions 22.4 r3-s1 Vulnerable ·Juniper
  • cpe:2.3:o:juniper:junos_os_evolved:23.2:-:*:*:*:*:*:* Versions 23.2 Vulnerable ·Juniper
  • cpe:2.3:o:juniper:junos_os_evolved:23.2:r1:*:*:*:*:*:* Versions 23.2 r1 Vulnerable ·Juniper
  • cpe:2.3:o:juniper:junos_os_evolved:23.2:r1-s1:*:*:*:*:*:* Versions 23.2 r1-s1 Vulnerable ·Juniper
  • cpe:2.3:o:juniper:junos_os_evolved:23.2:r1-s2:*:*:*:*:*:* Versions 23.2 r1-s2 Vulnerable ·Juniper
  • cpe:2.3:o:juniper:junos_os_evolved:23.2:r2:*:*:*:*:*:* Versions 23.2 r2 Vulnerable ·Juniper
  • cpe:2.3:o:juniper:junos_os_evolved:23.4:-:*:*:*:*:*:* Versions 23.4 Vulnerable ·Juniper
  • cpe:2.3:o:juniper:junos_os_evolved:23.4:r1:*:*:*:*:*:* Versions 23.4 r1 Vulnerable ·Juniper
  • cpe:2.3:o:juniper:junos_os_evolved:23.4:r1-s1:*:*:*:*:*:* Versions 23.4 r1-s1 Vulnerable ·Juniper
  • cpe:2.3:o:juniper:junos_os_evolved:23.4:r2:*:*:*:*:*:* Versions 23.4 r2 Vulnerable ·Juniper

Remediation

  • Fix · CNA Junos OS Evolved (Juniper Networks) Fixed in 21.4R3-S7-EVO, 22.2R3-S4-EVO, 22.3R3-S3-EVO, 22.4R3-S2-EVO, 23.2R2-S1-EVO, 23.4R1-S2-EVO, 23.4R2-EVO

Timeline

  1. 2026-10-02 Threatist record created from CVE-2026-21911
  2. 2026-10-03 Alias added: GHSA-6fvr-r66p-5w4v

References

Advisory 2

  • TI-2026-17602 Junos OS Evolved: PTX Series: A vulnerability allows a unauthenticated, network-based attacker to execute code as root CVSS 4.0CRITICAL 9.3
  • TI-2026-17601 Junos OS and Junos OS Evolved: Configuration of a specific SSH option results in mgd crash CVSS 4.0MEDIUM 6.7
  • TI-2023-04136 Improper input validation in Juniper Junos OS CVSS 3.1HIGH 7.5
  • TI-2026-74215 Stack-based buffer overflow in Junos OS rpd triggered by BGP peers CVSS 4.0CRITICAL 9.3
  • TI-2026-74211 Authentication bypass in Juniper J-Web allows pre-auth CGI execution CVSS 4.0CRITICAL 9.3
  • TI-2021-00146 Junos OS and Junos OS Evolved: Upon receipt of a specific BGP FlowSpec message network traffic may be disrupted. CVSS 3.1CRITICAL 10.0
See all 249 →

Sources

This product uses the NVD API but is not endorsed or certified by the NVD. Sources and licences