High priorityDisclosed

Advisory · CVE-2026-101944

Integer overflow in Junos rpd lets crafted EVPN updates crash the daemon

An integer overflow or wraparound vulnerability in the routing protocol daemon (rpd) of Junos OS and Junos OS Evolved lets an attacker cause a denial of service via specially crafted EVPN route updates from an accepted EVPN BGP peer. 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-2026-101944
CWE-190
Action timing
Immediate
ELI5

Explain it like I’m five

A counter in route processing wraps around, and the daemon's arithmetic failure becomes a routing outage.

SIMPLIFIED_ATTACK_PATH03 STEPS
  1. 01Trigger input

    An attacker sends the crafted protocol traffic described for CVE-2026-101944.

  2. 02Weakness trips

    The daemon mishandles the input through the integer overflow or wraparound weakness.

  3. 03Impact lands

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

What happened

Juniper disclosed CVE-2026-101944 in its October 2026 security release: an integer overflow or wraparound vulnerability (CWE-190) in rpd. Specially crafted EVPN route updates from an accepted EVPN BGP peer can deny 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 following EVPN route updates with extreme values from accepted peers.
  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

Accepted peers are still untrusted input sources. Patch, and keep EVPN peer lists tight.