CVE-2026-102080
Junos OS: MX Series: Malformed SyncE or PTP clock input causes continuous RE switchover
Juniper Networks Junos OSNetwork & edge
CVSS
5.3MediumExploitationNo known exploitationNot in CISA KEV, which does not prove it is unexploitedCISA KEV
Exploit odds (EPSS)0.18%Chance of exploitation activity in the next 30 days, higher than 7% of CVEs. Scored 23 Oct 2026FIRST EPSS
What fixes it
- 23.2R2-S7.7Junos OSCVE List
- 23.4R2-S8.13Junos OSCVE List
- 24.2R2-S5.5Junos OSCVE List
- 24.4R2-S4Junos OSCVE List
- 25.2R2-S1Junos OSCVE List
- 25.4R1-S2Junos OSCVE List
A fixed version on one release line is not the upgrade target for every line. Check your exact version and any vendor backports.
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.
Text from CVE List
Affected versions 6
- Junos OSaffected: all versions before 23.2R2-S7.7CVE List
- Junos OSaffected: 23.4 before 23.4R2-S8.13CVE List
- Junos OSaffected: 24.2 before 24.2R2-S5.5CVE List
- Junos OSaffected: 24.4 before 24.4R2-S4CVE List
- Junos OSaffected: 25.2 before 25.2R2-S1CVE List
- Junos OSaffected: 25.4 before 25.4R1-S2CVE List