CVE-2024-30402: Junos OS and Junos OS Evolved: The l2ald crashes on receiving telemetry messages from a specific subscription

Severity: medium (CVSS 5.3 v3.1)
Exploited in the wild: not listed in CISA KEV
EPSS: 0.5% probability of exploitation in the next 30 days
Public exploit or detection template: none known
Published: 2024-04-12 · updated 2026-06-17
Weakness: CWE-754

Description

An Improper Check for Unusual or Exceptional Conditions vulnerability in the Layer 2 Address Learning Daemon (l2ald) of Juniper Networks Junos OS and Junos OS Evolved allows an unauthenticated, adjacent attacker to cause a Denial of Service (DoS). When telemetry requests are sent to the device, and the Dynamic Rendering Daemon (drend) is suspended, the l2ald crashes and restarts due to factors outside the attackers control. Repeated occurrences of these events causes a sustained DoS condition. This issue affects: Junos OS: * All versions earlier than 20.4R3-S10; * 21.2 versions earlier than 21.2R3-S7; * 21.4 versions earlier than 21.4R3-S5; * 22.1 versions earlier than 22.1R3-S4; * 22.2 versions earlier than 22.2R3-S3; * 22.3 versions earlier than 22.3R3-S1; * 22.4 versions earlier than 22.4R3; * 23.2 versions earlier than 23.2R1-S2, 23.2R2. Junos OS Evolved: * All versions earlier than 21.4R3-S5-EVO; * 22.1-EVO versions earlier than 22.1R3-S4-EVO; * 22.2-EVO versions earlier than 22.2R3-S3-EVO; * 22.3-EVO versions earlier than 22.3R3-S1-EVO; * 22.4-EVO versions earlier than 22.4R3-EVO; * 23.2-EVO versions earlier than 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 (+75) — fixed in 20.4
Juniper Networks Junos OS Evolved: before 21.4; 21.4, 21.4-r1, 21.4-r1-s1, 21.4-r1-s2, 21.4-r2, 21.4-r2-s1 (+45) — fixed in 21.4

How to fix

Upgrade to a fixed version: Juniper Junos OS 20.4; Juniper Networks Junos OS Evolved 21.4. Check the vendor advisory for mitigations.

References

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