An Improper Validation of Syntactic Correctness of Input vulnerability in the Web-Filtering module of Juniper Networks Junos OS on SRX Series allows an unauthenticated, network-based attacker to 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.

This issue affects Junos OS on SRX Series:

• 23.2 versions from 23.2R2-S2 before 23.2R2-S5, 
• 23.4 versions from 23.4R2-S1 before 23.4R2-S5,
• 24.2 versions before 24.2R2-S2,
• 24.4 versions before 24.4R1-S3, 24.4R2.

Earlier versions of Junos are also affected, but no fix is available.

To be exposed to this issue web-filtering needs to be configured as follows:

[ security utm utm-policy <utm policy name> web-filtering http-profile <name> ]
[ security policies ... policy <security policy name> then permit application-services utm-policy <utm policy name> ]

Juniper SIRT is not aware of any malicious exploitation of this vulnerability.

This issue was found during internal product security testing or research.

The following software releases have been updated to resolve this specific issue: 23.2R2-S5, 23.4R2-S5, 24.2R2-S2, 24.4R1-S3, 24.4R2, 25.2R1, and all subsequent releases.

This issue is being tracked as 1876037 which is visible on the Customer Support website.

Note: Juniper SIRT's policy is not to evaluate releases which are beyond End of Engineering (EOE) or End of Life (EOL).

There are no known workarounds for this issue.

2026-01-14: Initial Publication

• KB16613: Overview of the Juniper Networks SIRT Quarterly Security Bulletin Publication Process [juniper.net]
• KB16765: In which releases are vulnerabilities fixed? [juniper.net]
• KB16446: Common Vulnerability Scoring System (CVSS) and Juniper's Security Advisories [juniper.net]
• Report a Security Vulnerability - How to Contact the Juniper Networks Security Incident Response Team