High priorityDisclosed

Advisory · CVE-2026-101941

NULL pointer flaw in Junos rpd lets a BGP neighbor crash the daemon under policy tracing

A NULL pointer dereference in the routing protocol daemon (rpd) of Junos OS and Junos OS Evolved lets a configured BGP neighbor cause a denial of service via a BGP route update when specific routing-policy resolution-map and policy event-tracing configuration is enabled. Juniper rates it CVSS 4.0 8.7 (CVSS 3.1 7.5).

Advisory published October 14, 2026Independent summary
Vendor
Juniper Networks
Product
Junos OS
Identifier / CWE
CVE-2026-101941
CWE-476
Action timing
Immediate
ELI5

Explain it like I’m five

Turning on policy tracing for debugging quietly arms a crash that any configured neighbor can trigger.

SIMPLIFIED_ATTACK_PATH03 STEPS
  1. 01Trigger input

    An attacker sends the crafted protocol traffic described for CVE-2026-101941.

  2. 02Weakness trips

    The daemon mishandles the input through the null pointer dereference weakness.

  3. 03Impact lands

    The routing or control-plane daemon crashes or misbehaves as described.

What happened

Juniper disclosed CVE-2026-101941 in its October 2026 security release: a NULL pointer dereference (CWE-476) in rpd. A configured BGP neighbor’s route update triggers it when specific routing-policy resolution-map and policy event-tracing configuration is enabled, denying service.

Juniper’s JSA112187 lists the affected service releases and the October 2026 service release thresholds that carry the fix. Match your exact release to the advisory rather than guessing here.

What to do

  1. Inventory every Junos OS deployment, including test, training, and individually managed instances.
  2. Apply the vendor fix or upgrade exactly as directed in the linked vendor bulletin or advisory.
  3. Restrict network access to Junos OS while remediation is underway, especially for internet-facing instances.
  4. Review application and server logs for rpd crashes while policy event-tracing is enabled and BGP updates arrive from neighbors.
  5. Check for accounts, content, or configuration created outside normal change processes, and rotate exposed credentials where access cannot be ruled out.
  6. Verify the deployed version or patch level after remediation.

Management note

Debug features left on in production are liabilities. Patch, and turn policy tracing off when the ticket closes.