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

published 2023-01-12 3 y ago modified 2026-06-17 4 mo ago also EUVD-2023-26554

cvss: 7.5; version 3.1, CNA
cisa kev: Not listed; not in CISA's catalog
epss: 0.6%; EPSS 0.6% chance of exploitation in 30 days, percentile 50%
public exploits: 0; none known

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.

Patch / fix

fixed in 1

Juniper Networks Junos OS 19.4R3-S9, 20.3R3-S6, 20.4R3-S4, 21.2R3-S3

CISA SSVC

Exploitation: none
Automatable: no
Technical impact: partial
Assessed: 19 mo ago (2025-04-07)

Exploit prediction

0.63% chance of exploitation in the next 30 days, higher than 50% of all scored CVEs (FIRST EPSS, 2026-11-08).

CVSS scores

assigned by	version	score	vector
CNA	3.1	7.5	CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

Affected products

Juniper Networks Junos OS

Classification

Weakness

CWE-755 Improper Handling of Exceptional Conditions

References

kb.juniper.net /JSA70187
vendor-advisory

Sources

CVE List CVE-2023-22391
NVD CVE-2023-22391

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Summary