CVE-2024-21603Network attack vector

Device restart via scaled SCU/DCU statistics gathering

Published Jan 12, 2024 · Updated Jun 17, 2025

Denial of service in the Junos OS kernel allows remote authenticated users to restart affected MX Series devices through SNMP or CLI. With more than 10 SCU/DCU route classes configured, gathering usage statistics creates a kernel vmcore and restarts the routing engine. Only MX Series systems with MPC10, MPC11, or LC9600 hardware, and MX304 systems, are affected; repeated requests sustain the outage.

CVSS severity6.5
Medium
EPSS probability0.51%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Denial of service in the Junos OS kernel allows remote authenticated users to restart affected MX Series devices through SNMP or CLI. With more than 10 SCU/DCU route classes configured, gathering usage statistics creates a kernel vmcore and restarts the routing engine. Only MX Series systems with MPC10, MPC11, or LC9600 hardware, and MX304 systems, are affected; repeated requests sustain the outage.

The record

CVE
CVE-2024-21603
Published
Jan 12, 2024
Updated
Jun 17, 2025
Vendor
Juniper Networks
Product
Junos OS
Classifications
CWE-754, T1499.004
Attack vector
network
Privileges
authenticated

Timeline

How it unfolded

  1. Jan 12, 2024CVE publishedPublication date reported by the CVE source.
  2. Jun 17, 2025Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=0 <20.4R3-S9
  2. Affected versionversion=21.2 <21.2R3-S6
  3. Affected versionversion=21.3 <21.3R3-S5
  4. Affected versionversion=21.4 <21.4R3
  5. Affected versionversion=22.1 <22.1R3
  6. Affected versionversion=22.2 <22.2R2
  7. Affected versionversion=22.3 <22.3R2

What conditions does exploitation require?

Attack vectornetwork
Required privilegesauthenticated

What is affected?

Juniper Networks · Junos OSversion=0 <20.4R3-S9; version=21.2 <21.2R3-S6; version=21.3 <21.3R3-S5; version=21.4 <21.4R3; version=22.1 <22.1R3; version=22.2 <22.2R2; version=22.3 <22.3R2

Published CVSS scores

6.5Juniper NetworksCVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

Daily unique IPsNo honeypot observations are available for this CVE in the selected window.

No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-754Improper Check for Unusual or Exceptional Conditions
T1499.004Endpoint Denial of Service: Application or System Exploitation

Public exploit references

No public exploit references are available in this record.

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

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Your stack

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