CVE-2026-21913
Junos OS: EX4000: A high volume of traffic destined to the device leads to a crash and restart
- State
- Published
- Severity
- 8.7 High
- Published
- Jan 15, 2026
- Updated
- Jan 15, 2026
- Reserved
- Jan 5, 2026
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.
Scores
| CVSS | Score | Vector | Source |
|---|---|---|---|
| 4.0 | 8.7 High | CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:L/AU:Y/R:A/RE:M | juniper |
| 3.1 | 7.5 High | CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H | juniper |
Weaknesses
- CWE-1419 Incorrect Initialization of Resource
Affected Products
| Product | Versions |
|---|---|
Junos OSJuniper Networks |
|
References
- https://supportportal.juniper.net/JSA106014vendor-advisory
- https://kb.juniper.net/JSA106014vendor-advisory
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