CVE-2026-101970 Juniper Networks CVE debrief

Who should care

Administrators and security teams responsible for Junos OS and Junos OS Evolved systems, especially those using sparse mode PIM, should assess exposure and prioritize updates to non-vulnerable versions.

Why it matters

CVE-2026-101970 is a medium-severity vulnerability in Junos OS and Junos OS Evolved that can cause the routing daemon to crash. It requires attention from administrators and security teams to assess exposure and apply necessary updates.

• Crash of the routing daemon, potentially disrupting network operations
• Need for validation and updates to ensure system stability and security

Technical summary

The vulnerability is a Use After Free issue in the rpd PIM Join/Prune processing of Junos OS and Junos OS Evolved. An unauthenticated adjacent attacker can exploit this by sending specific PIM messages when sparse mode PIM is configured, causing the routing daemon to crash. The vulnerability has a medium severity score and requires attention from administrators and security teams to assess exposure and apply necessary updates. The affected products are Junos OS and Junos OS Evolved, and the vulnerability can be mitigated by updating to non-vulnerable versions.

Defensive priority

Medium priority for Junos OS and Junos OS Evolved systems, focusing on validating and updating to non-vulnerable versions.

Recommended defensive actions

• Validate and update Junos OS and Junos OS Evolved to non-vulnerable versions
• Review and apply vendor-provided patches
• Monitor systems for potential crashes or anomalies
• Review compensating controls for exposed systems while remediation is scheduled and verified
• Check relevant monitoring, detection, and logs for exposed assets that need extra review
• Track exceptions, retest remediated assets, and close the item only after evidence is documented
• Confirm whether affected product deployments exist in managed environments and assign an owner for follow-up

Evidence notes

The CVE record and source item provide details on the vulnerability, including its description, affected versions, and references to vendor advisories. The vulnerability has a medium severity score of 6.5 and is tracked as CVE-2026-101970. The source item and CVE record provide evidence of the vulnerability's existence and details on its impact. Defenders should verify affected scope, severity, and vendor guidance.

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.