#VU121698 Improper Validation of Syntactic Correctness of Input in Juniper Junos OS - CVE-2026-21917

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Main Vulnerability Database Vulnerabilities #VU121698

#VU121698 Improper Validation of Syntactic Correctness of Input in Juniper Junos OS - CVE-2026-21917

Published: January 20, 2026


Vulnerability identifier: #VU121698
Vulnerability risk: Medium
CVSSv4.0: CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N/E:U/U:Green
CVE-ID: CVE-2026-21917
CWE-ID: CWE-1286
Exploitation vector: Remote access
Exploit availability: No public exploit available
Vulnerable software:
Juniper Junos OS
Software vendor:
Juniper Networks, Inc.

Description

The vulnerability allows a remote non-authenticated attacker to perform a denial of service (DoS) attack.

The vulnerability exists due to improper validation of syntactic correctness of input error in the Web-Filtering module. A remote non-authenticated attacker can cause a Denial-of-Service (DoS) If an SRX device configured for UTM Web-Filtering receives a specifically malformed SSL packet, this will cause an FPC crash and restart.


Remediation

Install updates from vendor's website.

External links