CVE-2024-30380: Junos OS and Junos OS Evolved: l2cpd crash upon receipt of a specific TLV

Severity: medium (CVSS 6.5 v3.1)
Exploited in the wild: not listed in CISA KEV
EPSS: 0.3% probability of exploitation in the next 30 days
Public exploit or detection template: none known
Published: 2024-04-16 · updated 2026-06-17
Weakness: CWE-755

Description

An Improper Handling of Exceptional Conditions vulnerability in Juniper Networks Junos OS and Junos OS Evolved allows an adjacent unauthenticated attacker to cause a Denial of Service (DoS), which causes the l2cpd process to crash by sending a specific TLV. The l2cpd process is responsible for layer 2 control protocols, such as STP, RSTP, MSTP, VSTP, ERP, and LLDP. The impact of the l2cpd crash is reinitialization of STP protocols (RSTP, MSTP or VSTP), and MVRP and ERP, leading to a Denial of Service. Continued receipt and processing of this specific TLV will create a sustained Denial of Service (DoS) condition. This issue affects: Junos OS: all versions before 20.4R3-S9, from 21.2 before 21.2R3-S7, from 21.3 before 21.3R3-S5, from 21.4 before 21.4R3-S4, from 22.1 before 22.1R3-S4, from 22.2 before 22.2R3-S2, from 22.3 before 22.3R2-S2, 22.3R3-S1, from 22.4 before 22.4R2-S2, 22.4R3, from 23.2 before 23.2R1-S1, 23.2R2; Junos OS Evolved: all versions before 21.2R3-S7, from 21.3 before 21.3R3-S5-EVO, from 21.4 before 21.4R3-S5-EVO, from 22.1 before 22.1R3-S4-EVO, from 22.2 before 22.2R3-S2-EVO, from 22.3 before 22.3R2-S2-EVO, 22.3R3-S1-EVO, from 22.4 before 22.4R2-S2-EVO, 22.4R3-EVO, from 23.2 before 23.2R1-S1-EVO, 23.2R2-EVO.

Affected products

Juniper Junos OS: before 20.4; 20.4, 20.4-r1, 20.4-r1-s1, 20.4-r2, 20.4-r2-s1, 20.4-r2-s2 (+80) — fixed in 20.4
Juniper Networks Junos OS Evolved: before 21.2; 21.2, 21.2-r1, 21.2-r1-s1, 21.2-r1-s2, 21.2-r2, 21.2-r2-s1 (+64) — fixed in 21.2

How to fix

Upgrade to a fixed version: Juniper Junos OS 20.4; Juniper Networks Junos OS Evolved 21.2. Check the vendor advisory for mitigations.

References

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