CVE-2026-102080

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

State: Published
Severity: 6.0 Medium
Published: Oct 14, 2026
Updated: Oct 14, 2026
Reserved: Sep 28, 2026

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.

Scores

CVSS	Score	Vector	Source
4.0	6.0 Medium	CVSS:4.0/AV:A/AC:L/AT:P/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:L/AU:Y/R:U/RE:M	juniper
3.1	5.3 Medium	CVSS:3.1/AV:A/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H	juniper

Weaknesses

CWE-413 Improper Resource Locking

Affected Products

Product	Versions
Junos OSJuniper Networks	before 23.2R2-S7.7Affected 23.4 to before 23.4R2-S8.13Affected 24.2 to before 24.2R2-S5.5Affected 24.4 to before 24.4R2-S4Affected 25.2 to before 25.2R2-S1Affected 25.4 to before 25.4R1-S2Affected

References

https://supportportal.juniper.net/JSA112178vendor-advisory

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