CVE-2026-33794 Junos OS Evolved: PTX Series: Receipt of repeated ECMP routing updates results in PFE crash

High 8.2 Published 9 Jul 2026 Updated 10 Jul 2026

An unauthenticated attacker can crash the PFE process on Juniper PTX routers by sending repeated ECMP routing updates, causing a denial of service.

Exploited in the wild: Not known
Login needed: Not needed
Attackable: Over the internet
Victim action needed: Not needed
Fix: None listed

What is CVE-2026-33794?

CVE-2026-33794 is a high-severity denial of service vulnerability in Juniper Junos Os Evolved, published on 9 Jul 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.

Official description

An Improper Check for Unusual or Exceptional Conditions vulnerability in the

advanced forwarding toolkit (evo-aftmand)

of Juniper Networks Junos OS Evolved on PTX Series allows an unauthenticated network-based attacker generating continuous routing updates, resulting in unilist ECMP routes, to crash the

evo-aftmand process on the PFE, leading to a Denial-of-Service (DoS). The conditions required for successful exploitation are based on a sequence of events that are outside an attacker's direct control.

Unified list (unilist) ECMP routes are a specific ECMP behavior where multiple equal-cost routes share a single logical next-hop list entry. The router treats them as one route with multiple next hops and load balances traffic across that unified list. Due to an issue processing unilist ECMP routing updates, internal state corruption may occur, especially in large-scale ECMP unilist deployments, leading to the evo-aftmand process crashing, resulting in an evo-aftmand-bx core. Manual intervention is required to recover by rebooting the system or restarting the FPC.

This issue affects Junos OS Evolved on PTX :

* from 24.4R2-EVO before 24.4R2-S3-EVO; * from 25.2 before 25.2R2-EVO.

Weakness: CWE-754

Which versions are affected by CVE-2026-33794?

It affects 1 product.

Products include Juniper Junos Os Evolved.

How do I fix CVE-2026-33794?

No fix has been published for CVE-2026-33794 yet. Limit exposure of the affected software until one is available.

Upgrade, then put limits on request size, rate and nesting depth so one client cannot exhaust the service. More about Denial of service.

Is CVE-2026-33794 being exploited?

There is no known exploitation of CVE-2026-33794 in the wild and no public exploit code.

All Juniper Junos Os Evolved vulnerabilities

Sources

Also known as GHSA-978v-9chj-92p2.