CVE-2026-101993 Juniper Networks CVE debrief

Who should care

Network administrators and security teams responsible for managing Juniper Networks Junos OS and Junos OS Evolved devices should assess exposure and prioritize patching. They should review configurations for VPLS automatic site-ID collision resolution and monitor network devices for potential exploitation attempts. Security teams should also verify and apply patches, especially for versions prior to 23.2R2-S7.7, 23.4R2-S8.13, 24.2R2-S5.5, 24.4R2-S5, 25.2R2

Why it matters

CVE-2026-101993 is a Reachable Assertion vulnerability in Juniper Networks Junos OS and Junos OS Evolved that can be exploited by an adjacent eBGP peer to cause a denial of service. Network administrators and security teams should prioritize verifying and applying patches, reviewing configurations, and monitoring network devices.

• Denial of service via rpd crash
• Potential network instability or downtime
• Need for patch verification and application
• Possible impact on network security posture

Technical summary

A Reachable Assertion vulnerability in the routing protocol daemon (rpd) of Juniper Networks Junos OS and Junos OS Evolved allows an adjacent eBGP peer to cause a denial of service via a VPLS signaling update when automatic site-ID negotiation is enabled. The vulnerability affects versions prior to 23.2R2-S7.7, 23.4R2-S8.13, 24.2R2-S5.5, 24.4R2-S5, 25.2R2-S2, 25.4R1-S3, and 26.2R1-S2. Network administrators and security teams should prioritize verifying and applying patches, reviewing configurations, and monitoring network devices.

Defensive priority

Network administrators and security teams should prioritize verifying and applying patches for Juniper Networks Junos OS and Junos OS Evolved, especially for versions prior to 23.2R2-S7.7, 23.4R2-S8.13, 24.2R2-S5.5, 24.4R2-S5, 25.2R2-S2, 25.4R1-S3, and 26.2R1-S2.

Recommended defensive actions

• Verify and apply patches for Juniper Networks Junos OS and Junos OS Evolved
• Review and update configurations for VPLS automatic site-ID collision resolution
• Monitor network devices for potential exploitation attempts
• 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
• Review the supplied official advisory or CVE record to validate affected scope, severity, and vendor guidance

Evidence notes

The CVE record and source item provide details on the vulnerability in Juniper Networks Junos OS and Junos OS Evolved, specifically in the routing protocol daemon (rpd), which can be exploited by an adjacent eBGP peer to cause a denial of service via a VPLS signaling update when automatic site-ID negotiation is enabled.

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.