CVE-2026-21913
7.5 · HIGHOverview
CVE-2026-21913 is a high-severity vulnerability affecting juniper junos. It was published on January 15, 2026 and has a CVSS 3.1 base score of 7.5 (HIGH).
This vulnerability has a CVSS 3.1 base score of 7.5, rated HIGH. It can be exploited remotely over the network. No authentication or special privileges are required for exploitation.
Technical Description
An Incorrect Initialization of Resource vulnerability in the Internal Device Manager (IDM) of Juniper Networks Junos OS on EX4000 models allows an unauthenticated, network-based attacker to cause a Denial-of-Service (DoS).
On EX4000 models with 48 ports (EX4000-48T, EX4000-48P, EX4000-48MP) a high volume of traffic destined to the device will cause an FXPC crash and restart, which leads to a complete service outage until the device has automatically restarted.
The following reboot reason can be seen in the output of 'show chassis routing-engine' and as a log message:
reason=0x4000002 reason_string=0x4000002:watchdog + panic with core dump
This issue affects Junos OS on EX4000-48T, EX4000-48P and EX4000-48MP:
* 24.4 versions before 24.4R2,
* 25.2 versions before 25.2R1-S2, 25.2R2.
This issue does not affect versions before 24.4R1 as the first Junos OS version for the EX4000 models was 24.4R1.
Remediation
Check the references section for vendor advisories and patches from juniper. Update junos to the latest patched version. If immediate patching is not possible, review the CVSS vector to understand the attack surface and apply compensating controls such as network segmentation or access restrictions.
Affected Products
| Vendor | Product | Versions | Status |
|---|
Frequently Asked Questions
What is CVE-2026-21913?
CVE-2026-21913 is a high-severity vulnerability affecting juniper junos. It was published on January 15, 2026 and has a CVSS 3.1 base score of 7.5 (HIGH).
How severe is CVE-2026-21913?
This vulnerability has a CVSS 3.1 base score of 7.5, rated HIGH. It can be exploited remotely over the network. No authentication or special privileges are required for exploitation.
How do I fix or remediate CVE-2026-21913?
Check the references section for vendor advisories and patches from juniper. Update junos to the latest patched version. If immediate patching is not possible, review the CVSS vector to understand the attack surface and apply compensating controls such as network segmentation or access restrictions.
How can CyberStrike help with CVE-2026-21913?
CyberStrike's AI-powered security agents can automatically detect CVE-2026-21913 across your infrastructure using autonomous pentesting, DAST scanning, and HackBrowser. The platform continuously monitors for known vulnerabilities and provides actionable remediation guidance prioritized by real-world exploitability.
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