CVE-2026-101987 Juniper Networks CVE debrief

Who should care

Network administrators and security teams responsible for Juniper Networks devices should assess their exposure and prioritize patching or mitigating this vulnerability. They need to verify SRv6 and Flexible Algorithm configurations, monitor network traffic for suspicious IS-IS SRv6 packets, and implement compensating controls for exposed systems. Additionally, they should review network segmentation and isolation measures to prevent potential attacks.

Why it matters

CVE-2026-101987 is a vulnerability in Junos OS and Junos OS Evolved that can cause a denial of service. Network administrators should prioritize patching or mitigating this vulnerability to prevent potential attacks.

• Denial of service attacks may occur if the vulnerability is exploited
• Network administrators need to verify SRv6 and Flexible Algorithm configurations
• Patching or mitigating this vulnerability is a priority for network security

Technical summary

The vulnerability is caused by an Improper Validation of Specified Quantity in Input in the routing daemon (rpd) of Juniper Networks Junos OS and Junos OS Evolved. An adjacent attacker can cause a denial of service by sending a specific IS-IS SRv6 packet when SRv6 and Flexible Algorithm are enabled. This issue affects network administrators and security teams responsible for Juniper Networks devices. They should assess their exposure and prioritize patching or mitigating this vulnerability to prevent potential denial-of-service attacks.

Defensive priority

Network administrators should prioritize patching or mitigating this vulnerability to prevent potential denial-of-service attacks.

Recommended defensive actions

• Review and apply patches from Juniper Networks
• Verify SRv6 and Flexible Algorithm configurations
• Monitor network traffic for suspicious IS-IS SRv6 packets
• Perform vulnerability scanning to identify exposed assets
• Implement compensating controls for exposed systems
• Review network segmentation and isolation measures
• Track and document remediation progress

Evidence notes

The CVE record and source item provide details about the vulnerability, including its description, affected products, and potential impact. However, there is limited information about the vulnerability's exploitation in the wild or specific attack vectors.

Sources and references

Methodology and review provenance

AI-assisted synthesis based on stored public vulnerability evidence. System validation, approval state, and publication status do not by themselves establish human review of this revision. PatchSiren helps prioritize defensive review and does not prove exposure or remediation on any system.