SB2026012060 - Improper Validation of Syntactic Correctness of Input in Juniper Junos OS
Published: January 20, 2026
Security Bulletin ID
SB2026012060
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 security vulnerability.
1) Improper Validation of Syntactic Correctness of Input (CVE-ID: CVE-2026-21917)
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.