CVE-2026-102080

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Denial-of-Service in Juniper Networks Junos OS MX Series

Publication date: 2026-10-14

Last updated on: 2026-10-14

Assigner: Juniper Networks, Inc.

Description

An Improper Resource Locking vulnerability in the clock synchronization daemon (clksyncd) of Juniper Networks Junos OS on MX Series allows a unauthenticated, logically adjacent attacker to cause a Denial-of-Service (DoS). If a SyncE or PTP upstream node sends a malformed message to an MX device equipped with SCBE3, a false 19.44MHz alarm is generated on the master RE. This leads to persistent RE switchovers and a clksyncd process crash. This issue is outside the attacker's direct control as it's a race condition. This issue affects Junos OS on MX Series: * All versions before 23.2R2-S7.7; * 23.4 versions before 23.4R2-S8.13; * 24.2 versions before 24.2R2-S5.5; * 24.4 versions before 24.4R2-S4; * 25.2 versions before 25.2R2-S1; * 25.4 versions before 25.4R1-S2.

CVSS Scores

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Meta Information

Published

2026-10-14

Last Modified

2026-10-14

Generated

2026-10-19

AI Q&A

2026-10-15

EPSS Evaluated

2026-10-18

NVD

CVE-2026-102080

EUVD

EUVD-2026-101464

Affected Vendors & Products

Vendor	Product	Version / Range
Juniper	Networks	Junos OS 0
Juniper	Networks	Junos OS 23.4
Juniper	Networks	Junos OS 24.2
Juniper	Networks	Junos OS 24.4
Juniper	Networks	Junos OS 25.2
Juniper	Networks	Junos OS 25.4

Helpful Resources

Exploitability

CWE

KEV

CWE ID	Description
CWE-413	The product does not lock or does not correctly lock a resource when the product must have exclusive access to the resource.

Attack-Flow Graph

Executive Summary

This vulnerability is an Improper Resource Locking issue in the clock synchronization daemon (clksyncd) of Juniper Networks Junos OS on MX Series devices. It allows an unauthenticated, logically adjacent attacker to cause a Denial-of-Service (DoS) by sending a malformed message from a SyncE or PTP upstream node to a device with SCBE3. This triggers a false 19.44MHz alarm on the master Routing Engine, leading to persistent RE switchovers and a clksyncd process crash.

Detection Guidance

Detection involves monitoring for persistent RE switchovers, clksyncd process crashes, or false 19.44MHz alarms on MX Series devices with SCBE3. Check system logs for clksyncd crashes or RE failovers. Juniper may provide specific CLI commands in security advisories.

Impact Analysis

This vulnerability can cause persistent switchovers of the Routing Engine (RE) and crashes of the clksyncd process, leading to Denial-of-Service (DoS) conditions. This disrupts network operations, causes downtime, and may require manual intervention to restore normal functionality.

Compliance Impact

This vulnerability causes Denial-of-Service (DoS) conditions through persistent RE switchovers and clksyncd process crashes, which could disrupt critical system operations. Such disruptions may impact availability requirements in compliance frameworks like GDPR (data processing continuity) and HIPAA (system availability for protected health information).

Mitigation Strategies

Upgrade Junos OS on affected MX Series devices to versions 23.2R2-S7.7 or later, 23.4R2-S8.13 or later, 24.2R2-S5.5 or later, 24.4R2-S4 or later, 25.2R2-S1 or later, or 25.4R1-S2 or later.
Isolate affected devices from SyncE or PTP upstream nodes sending malformed messages until patched.
Monitor for false 19.44MHz alarms or clksyncd crashes as indicators of exploitation.

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