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Junos OS: MX Series: Malformed SyncE or PTP clock input causes continuous RE switchover

Juniper Junos OS · CVE-2026-102080
0 news outlets1 CERTs and agencies0 researchers

What is it?

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.

Evidence

CERTs and agencies (1)

Exploitation

  • Public proof of concept
  • Exploited in the wild
  • Listed as known exploited
CVSS
5.3
EPSS
0.2%
First seen
9 h ago
Status
confirmed

All Juniper vulnerabilities