CVE-2026-101976 Juniper Networks CVE debrief

Who should care

Network administrators and security teams responsible for managing Junos OS and Junos OS Evolved devices should assess exposure and prioritize patching vulnerable versions to prevent potential DoS attacks. They should also verify BGP peer configurations to prevent exploitation and monitor network for potential DoS attacks. Additionally, they should review compensating controls for exposed systems while remediation is scheduled and verified.

Why it matters

CVE-2026-101976 is a high-severity vulnerability in Junos OS and Junos OS Evolved that can cause an rpd crash when a specific BGP update is received. Network administrators and security teams should prioritize patching vulnerable versions to prevent potential DoS attacks.

• Potential DoS attacks against Junos OS and Junos OS Evolved devices
• Verification of BGP peer configurations to prevent exploitation
• Patching vulnerable versions to prevent potential crashes

Technical summary

An Out-of-bounds Write vulnerability in the routing protocol daemon (rpd) of Juniper Networks Junos OS and Junos OS Evolved allows an eBGP peer which has not negotiated four-octet-AS capability sending a specifically malformed BGP update to cause a Denial-of-Service (DoS). The vulnerability affects Junos OS and Junos OS Evolved devices and requires careful verification of BGP peer configurations to prevent exploitation. Network administrators and security teams should prioritize patching vulnerable versions to prevent potential DoS attacks.

Defensive priority

Network administrators should prioritize patching vulnerable Junos OS and Junos OS Evolved versions to prevent potential DoS attacks.

Recommended defensive actions

• Patch vulnerable Junos OS and Junos OS Evolved versions
• Verify BGP peer configurations to prevent exploitation
• Monitor network for potential DoS attacks
• 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, CVSS score, and affected versions. The vulnerability has a CVSS score of 7.5 and is considered high-severity. The source item provides additional information on the vulnerability, including its impact on Junos OS and Junos OS Evolved devices. Defenders should verify affected scope, severity, and vendor guidance to assess exposure and prioritize patching vulnerable versions.

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.