High priorityDisclosed

Advisory · CVE-2026-102028

NULL pointer flaw in Junos rpd lets a BGP peer crash it over one session with L2VPN autodiscovery

A NULL pointer dereference vulnerability in the routing protocol daemon (rpd) of Junos OS and Junos OS Evolved lets a remote BGP peer cause a denial of service when multiple UPDATEs occur over a single TCP session with bgp family l2vpn auto-discovery-only configured. 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-2026-102028
CWE-476
Action timing
Immediate
ELI5

Explain it like I’m five

It takes a sequence, not a single packet: several updates on one session walk the daemon into a null dereference.

SIMPLIFIED_ATTACK_PATH03 STEPS
  1. 01Trigger input

    An attacker sends the crafted protocol traffic described for CVE-2026-102028.

  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-2026-102028 in its October 2026 security release: a NULL pointer dereference (CWE-476) in rpd. A remote BGP peer can deny service when multiple UPDATEs occur over a single TCP session and bgp family l2vpn auto-discovery-only is configured.

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 after bursts of BGP updates on sessions with l2vpn auto-discovery-only configured.
  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

Sequence bugs survive spot checks. Patch, and watch for rpd restarts clustered after session churn.