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Fencer Intel
medium 5.3

CVE-2026-102080 json

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

published 26d ago modified 25d ago also EUVD-2026-101464

cvss
5.3
version 3.1, CNA
cisa kev
Not listed
not in CISA's catalog
epss
0.2%
EPSS 0.2% chance of exploitation in 30 days, percentile 7%
public exploits
0
none known

Summary

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.

Patch / fix

  • Juniper Networks Junos OS 23.2R2-S7.7, 23.4R2-S8.13, 24.2R2-S5.5, 24.4R2-S4, 25.2R2-S1, 25.4R1-S2

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CISA SSVC

Exploitation
none
Automatable
no
Technical impact
partial
Assessed
26d ago

Exploit prediction

0.18% chance of exploitation in the next 30 days, higher than 7% of all scored CVEs (FIRST EPSS, 2026-11-09).

CVSS scores

assigned by version score vector
CNA 3.1 5.3 CVSS:3.1/AV:A/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H
CNA 4.0 6.0 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
CNA 4.0 6.0 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/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:Y/R:U/V:X/RE:M/U:X

Affected products

  • Juniper Networks Junos OS

Classification

Weakness
  • CWE-413 Improper Resource Locking

References

Sources

Fencer Intel keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.