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Vulnerabilities

Vulnerability · CVE-2024-21603

An Improper Check for Unusual or Exceptional Conditions vulnerability in the kernel of Juniper Network Junos OS on MX Series allows a network based attacker with low p…

Published Jan 12, 2024 · catalog updated Jun 17, 2026 · the affected product

Last checked Nov 7, 2026. A connected source was read within the last 7 days.

Check if you run it

No confirmed exploitation is on record for CVE-2024-21603. EPSS is 0.51%. Act only if a listed version of the affected product is installed.

Gaps on this record

  • No plain product name is stored. The page cannot tell you which product to check.
  • No vendor fix or required action is stored. Compare the linked advisory before you change production.

Same product and reporting

Severity
Medium6.5
Known exploitation
Not in CISA/VulnCheck KEV
EPSS
0.51%
Remediation
Advisory link
Affected products
cpe juniper/junos

An Improper Check for Unusual or Exceptional Conditions vulnerability in the kernel of Juniper Network Junos OS on MX Series allows a network based attacker with low privileges to cause a denial of service. If a scaled configuration for Source class usage (SCU) / destination class usage (DCU) (more than 10 route classes) is present and the SCU/DCU statistics are gathered by executing specific SNMP requests or CLI commands, a 'vmcore' for the RE kernel will be seen which leads to a device restart. Continued exploitation of this issue will lead to a sustained DoS. This issue only affects MX Series devices with MPC10, MPC11 or LC9600, and MX304. No other MX Series devices are affected. This issue affects Juniper Networks Junos OS: * All versions earlier than 20.4R3-S9; * 21.2 versions earlier than 21.2R3-S6; * 21.3 versions earlier than 21.3R3-S5; * 21.4 versions earlier than 21.4R3; * 22.1 versions earlier than 22.1R3; * 22.2 versions earlier than 22.2R2; * 22.3 versions earlier than 22.3R2.

Are you affected?

Enter the version you run. The result uses only the ranges stored on this record.

The check returns affected, not affected, or incomplete. It does not guess a version that is missing from the record.

  • cpe juniper/junos20.4

How to fix CVE-2024-21603

What to do

Three questions, each answered from this record only. Confirm the vendor advisory before you patch.

Should you patch?

No confirmed exploitation is on record for CVE-2024-21603. EPSS is 0.51%. Act only if a listed version of the affected product is installed.

Which versions are affected?

Compare what you have installed with 20.4. Compare the installed version with the linked vendor advisory before you change production.

What should an analyst verify?

CWE-754. EPSS 0.51%. There is no CISA KEV listing. No Exploit-DB or Metasploit reference is linked. Use the source links for the original advisory.

Technology hubs

Juniper Junos OS security

Code

The project this record applies to. Exploit listings stay in References.

No public source repository is identified for this product.

Timeline

Detection, updates, and resolution for this record.

  1. Jan 12, 2024 · Monitored products — high

    Detected

    An Improper Check for Unusual or Exceptional Conditions vulnerability in the kernel of Juniper Network Junos OS on MX Series allows a network based attacker with low privileges to cause a denial of service. If a scaled configuration for Source class usage (SCU) / destination class usage (DCU) (more than 10 route classes) is present and the SCU/DCU statistics are gathered by executing specific SNMP

  2. Jun 17, 2026 · Monitored products — high

    Updated

    An Improper Check for Unusual or Exceptional Conditions vulnerability in the kernel of Juniper Network Junos OS on MX Series allows a network based attacker with low privileges to cause a denial of service. If a scaled configuration for Source class usage (SCU) / destination class usage (DCU) (more than 10 route classes) is present and the SCU/DCU statistics are gathered by executing specific SNMP

Sources

  • CVE.orgVulnerability recordCVE-2024-21603

    Official CVE identifier

    cve.org
  • Monitored products — highVendor advisoryCVE-2024-21603

    An Improper Check for Unusual or Exceptional Conditions vulnerability in the kernel of Juniper Network Junos OS on MX Series allows a network based attacker with low privileges to cause a denial of service. If a scaled configuration for Source class usage (SCU) / destination class usage (DCU) (more than 10 route classes) is present and the SCU/DCU statistics are gathered by executing specific SNMP

    nvd.nist.gov

References

Freshness

Last verified in this catalog Nov 7, 2026. Significant claims (KEV, EPSS, CVSS, affected ranges) come from the source rows above — open the original publisher for the authoritative advisory.

  • CVE.orgNov 7, 2026
  • Monitored products — highNov 7, 2026