Junos OS: EX4000: A high volume of traffic destined to the device leads to a crash and restart
Key facts
- Attack vector
- Network
- Privileges required
- None
- User interaction
- None
- Attack complexity
- Low
- Attack requirements
- None
- Impact type
- —
- Confidentiality · integrity · availability
- None · None · High
- Fix status
- Fixed
Attack profile from CVSS 4.0 · CNA. Fix status from CNA.
Summary
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.
Why it matters now
SSVC decision points
CISA ADP · SSVC 2.0.3
- Exploitation
- None
- Automatable
- Yes
- Technical impact
- Partial
The decision (Track, Attend, Act) also depends on your mission and well-being impact; see CISA's SSVC guide.
Affected products
| Vendor | Product | Affected versions | Fixed in | Status | Source |
|---|---|---|---|---|---|
| Juniper | Junos OS | 24.4 to before 24.4R2; 25.2 to before 25.2R1-S2, 25.2R2 | 24.4R2, 25.2R1-S2, 25.2R2 | Patch available | CNA |
- Junos OS VendorJuniper Affected 24.4 to before 24.4R2; 25.2 to before 25.2R1-S2, 25.2R2 Fixed in 24.4R2, 25.2R1-S2, 25.2R2 Patch available CNA
CPE configurations NVD · 11
| CPE | Versions | Role | Vendor |
|---|---|---|---|
| cpe:2.3:o:juniper:junos:24.4:-:*:*:*:*:*:* | 24.4 | Vulnerable | Juniper |
| cpe:2.3:o:juniper:junos:24.4:r1:*:*:*:*:*:* | 24.4 r1 | Vulnerable | Juniper |
| cpe:2.3:o:juniper:junos:24.4:r1-s2:*:*:*:*:*:* | 24.4 r1-s2 | Vulnerable | Juniper |
| cpe:2.3:o:juniper:junos:24.4:r1-s3:*:*:*:*:*:* | 24.4 r1-s3 | Vulnerable | Juniper |
| cpe:2.3:o:juniper:junos:25.2:-:*:*:*:*:*:* | 25.2 | Vulnerable | Juniper |
| cpe:2.3:o:juniper:junos:25.2:r1:*:*:*:*:*:* | 25.2 r1 | Vulnerable | Juniper |
| cpe:2.3:o:juniper:junos:25.2:r1-s1:*:*:*:*:*:* | 25.2 r1-s1 | Vulnerable | Juniper |
| cpe:2.3:o:juniper:junos:25.2:r2:*:*:*:*:*:* | 25.2 r2 | Vulnerable | Juniper |
| cpe:2.3:h:juniper:ex4000-48mp:-:*:*:*:*:*:*:* | not specified by NVD | Running on | Juniper |
| cpe:2.3:h:juniper:ex4000-48p:-:*:*:*:*:*:*:* | not specified by NVD | Running on | Juniper |
- cpe:2.3:o:juniper:junos:24.4:-:*:*:*:*:*:* Versions 24.4 Vulnerable ·Juniper
- cpe:2.3:o:juniper:junos:24.4:r1:*:*:*:*:*:* Versions 24.4 r1 Vulnerable ·Juniper
- cpe:2.3:o:juniper:junos:24.4:r1-s2:*:*:*:*:*:* Versions 24.4 r1-s2 Vulnerable ·Juniper
- cpe:2.3:o:juniper:junos:24.4:r1-s3:*:*:*:*:*:* Versions 24.4 r1-s3 Vulnerable ·Juniper
- cpe:2.3:o:juniper:junos:25.2:-:*:*:*:*:*:* Versions 25.2 Vulnerable ·Juniper
- cpe:2.3:o:juniper:junos:25.2:r1:*:*:*:*:*:* Versions 25.2 r1 Vulnerable ·Juniper
- cpe:2.3:o:juniper:junos:25.2:r1-s1:*:*:*:*:*:* Versions 25.2 r1-s1 Vulnerable ·Juniper
- cpe:2.3:o:juniper:junos:25.2:r2:*:*:*:*:*:* Versions 25.2 r2 Vulnerable ·Juniper
- cpe:2.3:h:juniper:ex4000-48mp:-:*:*:*:*:*:*:* Versions not specified by NVD Running on ·Juniper
- cpe:2.3:h:juniper:ex4000-48p:-:*:*:*:*:*:*:* Versions not specified by NVD Running on ·Juniper
Remediation
- Fix · CNA Junos OS (Juniper Networks) Fixed in 24.4R2, 25.2R1-S2, 25.2R2
Timeline
- 2026-10-02 Threatist record created from CVE-2026-21913
- 2026-10-03 Alias added: GHSA-p84c-pfqc-c27p
References
More Juniper Junos vulnerabilities
- TI-2023-18638 Junos OS: EX and SRX Series: A PHP vulnerability in J-Web allows an unauthenticated to… KEVCVSS 3.1CRITICAL 9.8
- TI-2020-01585 Out of Cycle Security Advisory: Junos OS: Security vulnerability in J-Web and web based (HTTP/HTTPS) services KEVCVSS 3.1CRITICAL 9.8
- TI-2015-04610 Assertion failure in ISC BIND named via TKEY queries KEVCVSS 3.1HIGH 7.5
- TI-2025-15550 Junos OS: An local attacker with shell access can execute arbitrary code KEVCVSS 4.0MEDIUM 6.7
- TI-2023-18644 Junos OS: SRX Series: A vulnerability in J-Web allows an unauthenticated attacker to upload and download arbitrary files KEVCVSS 3.1MEDIUM 5.3
- TI-2023-18640 Junos OS: EX Series: A vulnerability in J-Web allows an unauthenticated attacker to upload arbitrary files KEVCVSS 3.1MEDIUM 5.3
Sources
- CVE-2026-21913 · CVE Program
- CVE-2026-21913 · NVD
- FIRST EPSS
- GHSA-p84c-pfqc-c27p · GitHub Advisory Database · CC BY 4.0
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