CVE-2023-36839

Junos OS and Junos OS Evolved: An l2cpd crash will occur when specific LLDP packets are received

Published Oct 12, 2023 CVSS 3.1 · 6.5 Medium EPSS < 1% KEV · Not listed
Description

An Improper Validation of Specified Quantity in Input vulnerability in the Layer-2 control protocols daemon (l2cpd) of Juniper Networks Junos OS and Junos OS Evolved allows an unauthenticated adjacent attacker who sends specific LLDP packets to cause a Denial of Service(DoS).

This issue occurs when specific LLDP packets are received and telemetry polling is being done on the device. The impact of the l2cpd crash is reinitialization of STP protocols (RSTP, MSTP or VSTP), and MVRP and ERP. Also, if any services depend on LLDP state (like PoE or VoIP device recognition), then these will also be affected.

This issue affects:

Juniper Networks Junos OS



* All versions prior to 20.4R3-S8;
* 21.1 version 21.1R1 and later versions;
* 21.2 versions prior to 21.2R3-S5;
* 21.3 versions prior to 21.3R3-S4;
* 21.4 versions prior to 21.4R3-S3;
* 22.1 versions prior to 22.1R3-S2;
* 22.2 versions prior to 22.2R3;
* 22.3 versions prior to 22.3R2-S2;
* 22.4 versions prior to 22.4R2;




Juniper Networks Junos OS Evolved



* All versions prior to 20.4R3-S8-EVO;
* 21.1 version 21.1R1-EVO and later versions;
* 21.2 versions prior to 21.2R3-S5-EVO;
* 21.3 versions prior to 21.3R3-S4-EVO;
* 21.4 versions prior to 21.4R3-S3-EVO;
* 22.1 versions prior to 22.1R3-S2-EVO;
* 22.2 versions prior to 22.2R3-EVO;
* 22.3 versions prior to 22.3R2-S2-EVO;
* 22.4 versions prior to 22.4R1-S1-EVO;






Remediation

Vendor Solution

The following software releases have been updated to resolve this specific issue: Junos OS: 20.4R3-S8, 21.2R3-S5, 21.3R3-S4, 21.4R3-S3, 22.1R3-S2, 22.2R3, 22.3R2-S2, 22.3R3, 22.4R2, 23.2R1, and all subsequent releases. Junos OS Evolved: 20.4R3-S8-EVO, 21.2R3-S5-EVO, 21.3R3-S4-EVO, 21.4R3-S3-EVO, 22.1R3-S2-EVO, 22.2R3-EVO, 22.3R2-S2-EVO, 22.3R3-EVO, 22.4R1-S1-EVO, 22.4R2-EVO, 23.1R1-EVO, 23.1R2-EVO, 23.2R1-EVO


Vendor Workaround

If LLDP and its services are not required, customers can disable LLDP. Disabling telemetry polling also mitigates the issue. There are no other known workarounds for this issue.

Tracking

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Advisories

Source ID Title
EUVD EUVD EUVD-2023-40759 An Improper Validation of Specified Quantity in Input vulnerability in the Layer-2 control protocols daemon (l2cpd) of Juniper Networks Junos OS and Junos OS Evolved allows an unauthenticated adjacent attacker who sends specific LLDP packets to cause a Denial of Service(DoS). This issue occurs when specific LLDP packets are received and telemetry polling is being done on the device. The impact of the l2cpd crash is reinitialization of STP protocols (RSTP, MSTP or VSTP), and MVRP and ERP. Also, if any services depend on LLDP state (like PoE or VoIP device recognition), then these will also be affected. This issue affects: Juniper Networks Junos OS * All versions prior to 20.4R3-S8; * 21.1 version 21.1R1 and later versions; * 21.2 versions prior to 21.2R3-S5; * 21.3 versions prior to 21.3R3-S4; * 21.4 versions prior to 21.4R3-S3; * 22.1 versions prior to 22.1R3-S2; * 22.2 versions prior to 22.2R3; * 22.3 versions prior to 22.3R2-S2; * 22.4 versions prior to 22.4R2; Juniper Networks Junos OS Evolved * All versions prior to 20.4R3-S8-EVO; * 21.1 version 21.1R1-EVO and later versions; * 21.2 versions prior to 21.2R3-S5-EVO; * 21.3 versions prior to 21.3R3-S4-EVO; * 21.4 versions prior to 21.4R3-S3-EVO; * 22.1 versions prior to 22.1R3-S2-EVO; * 22.2 versions prior to 22.2R3-EVO; * 22.3 versions prior to 22.3R2-S2-EVO; * 22.4 versions prior to 22.4R1-S1-EVO;
References
History
Type Values Removed Values Added
Metrics ssvc

{'options': {'Automatable': 'no', 'Exploitation': 'none', 'Technical Impact': 'partial'}, 'version': '2.0.3'}

Weaknesses

Sources

Status
PUBLISHED
Assigner
juniper
Published
Updated
Sep 18, 2024, 6:03 PM
Reserved
Jun 27, 2023, 4:17 PM
Status
Modified
Published
Oct 12, 2023, 11:15 PM
Modified
Jun 17, 2026, 6:07 AM