CVE-2026-21917
7.5 · HIGHOverview
CVE-2026-21917 is a high-severity vulnerability affecting juniper junos. It was published on January 15, 2026 and has a CVSS 3.1 base score of 7.5 (HIGH).
This vulnerability has a CVSS 3.1 base score of 7.5, rated HIGH. It can be exploited remotely over the network. No authentication or special privileges are required for exploitation.
Technical Description
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.
Remediation
Check the references section for vendor advisories and patches from juniper. Update junos to the latest patched version. If immediate patching is not possible, review the CVSS vector to understand the attack surface and apply compensating controls such as network segmentation or access restrictions.
Affected Products
| Vendor | Product | Versions | Status |
|---|
Frequently Asked Questions
What is CVE-2026-21917?
CVE-2026-21917 is a high-severity vulnerability affecting juniper junos. It was published on January 15, 2026 and has a CVSS 3.1 base score of 7.5 (HIGH).
How severe is CVE-2026-21917?
This vulnerability has a CVSS 3.1 base score of 7.5, rated HIGH. It can be exploited remotely over the network. No authentication or special privileges are required for exploitation.
How do I fix or remediate CVE-2026-21917?
Check the references section for vendor advisories and patches from juniper. Update junos to the latest patched version. If immediate patching is not possible, review the CVSS vector to understand the attack surface and apply compensating controls such as network segmentation or access restrictions.
How can CyberStrike help with CVE-2026-21917?
CyberStrike's AI-powered security agents can automatically detect CVE-2026-21917 across your infrastructure using autonomous pentesting, DAST scanning, and HackBrowser. The platform continuously monitors for known vulnerabilities and provides actionable remediation guidance prioritized by real-world exploitability.
How CyberStrike Helps
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