CVE-2026-102086 Juniper Networks CVE debrief

Who should care

Defenders responsible for Juniper Networks Junos OS on SRX Series should assess exposure and prioritize patching. This includes reviewing and applying patches for affected versions, monitoring for suspicious DNS query patterns, and updating incident response plans for potential DoS attacks. Security teams should also review compensating controls and track exceptions for exposed systems.

Why it matters

Defenders should prioritize verifying and applying patches for affected Junos OS versions on SRX Series, as well as monitoring for suspicious DNS query patterns, to mitigate potential Denial-of-Service (DoS) attacks.

• Potential Denial-of-Service (DoS) due to FPC crash
• Need to verify and apply patches for affected Junos OS versions
• Requires monitoring for suspicious DNS query patterns

Technical summary

A NULL Pointer Dereference vulnerability in the DNS plugin of Juniper Networks Junos OS on SRX Series allows an unauthenticated, network-based attacker to cause a complete Denial-of-Service (DoS). When multiple DNS queries are received in a single flow session, where one query matches a Security Intelligence (SecIntel) feed and another query is sent for DNS Domain Generation Algorithm (DGA) analysis, an error in processing logging of these asynchronous tasks can lead to an FPC crash. The exact timing conditions are outside an attacker's direct control.

Defensive priority

Defenders should prioritize verifying and applying patches for affected Junos OS versions on SRX Series, as well as monitoring for suspicious DNS query patterns.

Recommended defensive actions

• Verify and apply patches for affected Junos OS versions on SRX Series
• Monitor for suspicious DNS query patterns
• Review and update incident response plans 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 affected versions and a reference to a vendor advisory. Affected Junos OS versions on SRX Series include all versions before 23.2R2-S7.7; from 23.4 before 23.4R2-S8.13; from 24.2 before 24.2R2-S5.5; from 24.4 before 24.4R2-S4; from 25.2 before 25.2R2-S1; from 25.4 before 25.4R1-S2. Defenders should verify and apply patches for these 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.