CVE-2023-22391: Junos OS: ACX2K Series: Receipt of a high rate of specific traffic will lead to a Denial of Service (DoS)

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: 2023-01-13 · updated 2026-06-17
Weakness: CWE-755

Description

A vulnerability in class-of-service (CoS) queue management in Juniper Networks Junos OS on the ACX2K Series devices allows an unauthenticated network-based attacker to cause a Denial of Service (DoS). Specific packets are being incorrectly routed to a queue used for other high-priority traffic such as BGP, PIM, ICMP, ICMPV6 ND and ISAKMP. Due to this misclassification of traffic, receipt of a high rate of these specific packets will cause delays in the processing of other traffic, leading to a Denial of Service (DoS). Continued receipt of this amount of traffic will create a sustained Denial of Service (DoS) condition. This issue affects Juniper Networks Junos OS on ACX2K Series: All versions prior to 19.4R3-S9; All 20.2 versions; 20.3 versions prior to 20.3R3-S6 on ACX2K Series; 20.4 versions prior to 20.4R3-S4 on ACX2K Series; All 21.1 versions; 21.2 versions prior to 21.2R3-S3 on ACX2K Series. Note: This issues affects legacy ACX2K Series PPC-based devices. This platform reached Last Supported Version (LSV) as of the Junos OS 21.2 Release.

Affected products

Juniper Junos OS: before 19.4; 19.4, 19.4-r1, 19.4-r1-s1, 19.4-r1-s2, 19.4-r1-s3, 19.4-r1-s4 (+66) — fixed in 19.4

How to fix

Upgrade to a fixed version: Juniper Junos OS 19.4. Check the vendor advisory for mitigations.

References

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