CVE-2023-28976: Junos OS: MX Series: If a specific traffic rate goes above the DDoS threshold it will lead to an FPC crash

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: 2023-04-17 · 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 an unauthenticated, network-based attacker to cause a Denial of Service (DoS). If specific traffic is received on MX Series and its rate exceeds the respective DDoS protection limit the ingress PFE will crash and restart. Continued receipt of this traffic will create a sustained DoS condition. This issue affects Juniper Networks Junos OS on MX Series: All versions prior to 19.1R3-S10; 19.2 versions prior to 19.2R3-S7; 19.3 versions prior to 19.3R3-S8; 19.4 versions prior to 19.4R3-S11; 20.2 versions prior to 20.2R3-S5; 20.4 versions prior to 20.4R3-S6; 21.1 versions prior to 21.1R3-S5; 21.2 versions prior to 21.2R3-S4; 21.3 versions prior to 21.3R3; 21.4 versions prior to 21.4R3; 22.1 versions prior to 22.1R2.

Affected products

Juniper Junos OS: before 19.1; 19.1, 19.1-r1, 19.1-r1-s1, 19.1-r1-s2, 19.1-r1-s3, 19.1-r1-s4 (+145) — fixed in 19.1

How to fix

Upgrade to a fixed version: Juniper Junos OS 19.1. Check the vendor advisory for mitigations.

References

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