CVE-2025-21596

Junos OS: SRX1500,SRX4100,SRX4200: Execution of low-privileged CLI command results in chassisd crash

Description

An Improper Handling of Exceptional Conditions vulnerability in the command-line processing of Juniper Networks Junos OS on SRX1500, SRX4100, and SRX4200 devices allows a local, low-privileged authenticated attacker executing the 'show chassis environment pem' command to cause the chassis daemon (chassisd) to crash and restart, resulting in a temporary Denial of Service (DoS). However, repeated execution of this command will eventually cause the chassisd process to fail to restart, impacting packet processing on the system. This issue affects Junos OS on SRX1500, SRX4100, SRX4200:  * All versions before 21.4R3-S9,  * from 22.2 before 22.2R3-S5,  * from 22.3 before 22.3R3-S4,  * from 22.4 before 22.4R3-S4,  * from 23.2 before 23.2R2-S3,  * from 23.4 before 23.4R2-S1.

Remediation

Solution:

  • The following software releases have been updated to resolve this specific issue: 21.4R3-S9, 22.2R3-S5, 22.3R3-S4, 22.4R3-S4, 23.2R2-S3, 23.4R2-S1, 24.2R1, and all subsequent releases.

Workaround:

  • Use access lists or firewall filters to limit access to the CLI only from trusted hosts and administrators. Utilize CLI authorization to disallow execution of the 'show chassis environment pem' command.

Category

6.8
CVSS
Severity: Medium
CVSS 4.0 •
CVSS 3.1 •
EPSS 0.03%
Vendor Advisory juniper.net
Affected: Juniper Networks Junos OS
Published at:
Updated at:

References

Link Tags
https://supportportal.juniper.net/JSA92864 vendor advisory

Frequently Asked Questions

What is the severity of CVE-2025-21596?
CVE-2025-21596 has been scored as a medium severity vulnerability.
How to fix CVE-2025-21596?
To fix CVE-2025-21596: The following software releases have been updated to resolve this specific issue: 21.4R3-S9, 22.2R3-S5, 22.3R3-S4, 22.4R3-S4, 23.2R2-S3, 23.4R2-S1, 24.2R1, and all subsequent releases.
Is CVE-2025-21596 being actively exploited in the wild?
As for now, there are no information to confirm that CVE-2025-21596 is being actively exploited. According to its EPSS score, there is a ~0% probability that this vulnerability will be exploited by malicious actors in the next 30 days.
What software or system is affected by CVE-2025-21596?
CVE-2025-21596 affects Juniper Networks Junos OS.
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