CVE-2023-44199: Junos OS: MX Series: In a PTP scenario a prolonged routing protocol churn can trigger an FPC reboot

Severity: high (CVSS 7.5 v3.1)
Exploited in the wild: not listed in CISA KEV
EPSS: 0.6% probability of exploitation in the next 30 days
Public exploit or detection template: none known
Published: 2023-10-13 · updated 2026-06-17
Weakness: CWE-754

Description

An Improper Check for Unusual or Exceptional Conditions vulnerability in the Packet Forwarding Engine (PFE) of Juniper Networks Junos OS on MX Series allows a network-based, unauthenticated attacker to cause a Denial of Service (DoS). On Junos MX Series platforms with Precision Time Protocol (PTP) configured, a prolonged routing protocol churn can lead to an FPC crash and restart. This issue affects Juniper Networks Junos OS on MX Series: * All versions prior to 20.4R3-S4; * 21.1 version 21.1R1 and later versions; * 21.2 versions prior to 21.2R3-S2; * 21.3 versions prior to 21.3R3-S5; * 21.4 versions prior to 21.4R3; * 22.1 versions prior to 22.1R3; * 22.2 versions prior to 22.2R1-S1, 22.2R2.

Affected products

Juniper Junos OS: before 20.4; 20.4, 20.4-r1, 20.4-r1-s1, 20.4-r2, 20.4-r2-s1, 20.4-r2-s2 (+53) — fixed in 20.4

How to fix

Upgrade to a fixed version: Juniper Junos OS 20.4. Check the vendor advisory for mitigations.

References

Get alerted when CVE-2023-44199 or the next vulnerability affects your stack