Main Vulnerability Database SB2026012060

SB2026012060 - Improper Validation of Syntactic Correctness of Input in Juniper Junos OS

Published: January 20, 2026

Security Bulletin ID SB2026012060

CSH Severity

Medium

Patch available

YES

Number of vulnerabilities 1

Exploitation vector Remote access

Highest impact Denial of service

Breakdown by Severity

Low
Medium
High
Critical

Description

This security bulletin contains information about 1 vulnerability.

1) Improper Validation of Syntactic Correctness of Input (CVE-ID: CVE-2026-21917)

CWE-ID: CWE-1286 - Improper Validation of Syntactic Correctness of Input

CVSSv4: 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

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 update from vendor's website.

References

https://supportportal.juniper.net/s/article/2026-01-Security-Bulletin-Junos-OS-SRX-Series-Specifically-malformed-SSL-packet-causes-FPC-crash-CVE-2026-21917