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

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

- **Severity:** High 8.2 (`CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:L/AU:Y/R:U/V:C/RE:M/U:Green`)
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Over the internet
- **Victim action needed:** Not needed
- **Fix available:** No
- **Published:** 9 Jul 2026
- **Updated:** 10 Jul 2026
- **Also known as:** GHSA-978v-9chj-92p2

## 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 (Improper Check for Unusual or Exceptional Conditions)

## Which versions are affected by CVE-2026-33794?

It affects 1 product.


Products: 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.

## Is CVE-2026-33794 being exploited?

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

## Other vulnerabilities in Juniper Junos Os Evolved

- [CVE-2026-21902](https://insights.sbomify.com/CVE-2026-21902/): Junos OS Evolved: PTX Series: A vulnerability allows a unauthenticated, network-based attacker to execute code as root (critical 9.3)
- [CVE-2023-28983](https://insights.sbomify.com/CVE-2023-28983/): Junos OS Evolved: Shell Injection vulnerability in the gNOI server (high 8.8)
- [CVE-2025-21599](https://insights.sbomify.com/CVE-2025-21599/): Denial of service in Junos OS Evolved (high 8.7)
- [CVE-2024-47502](https://insights.sbomify.com/CVE-2024-47502/): Junos OS Evolved: TCP session state is not always cleared on the Routing Engine leading to DoS (high 8.7)
- [CVE-2024-39531](https://insights.sbomify.com/CVE-2024-39531/): Junos OS Evolved: ACX 7000 Series: Protocol specific DDoS configuration affects other protocols (high 8.7)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-33794 and fix it if it is affected.

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

Affected product: Juniper Junos Os Evolved. No package-level version data is available, so check the vendor advisory linked from the reference page.

Task:
1. Search the dependency manifests and lockfiles (for example package.json, package-lock.json, requirements.txt, poetry.lock, uv.lock, pom.xml, build.gradle, go.mod, Cargo.lock, Gemfile.lock) and any Dockerfiles for the affected packages, including transitive dependencies.
2. If an affected version is in use, upgrade it to the fixed version for its release line with the project's package manager, so the lockfile is regenerated. Prefer the smallest upgrade that fixes it.
3. If there is no fix, or the upgrade would break the build, do not guess: explain the risk and the safest workaround instead.
4. Run the tests and summarise what changed and why.
5. If nothing in the project is affected, say so and change nothing.

Reference: https://insights.sbomify.com/CVE-2026-33794/ (Markdown: https://insights.sbomify.com/CVE-2026-33794/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-33794
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-33794
- OSV: https://osv.dev/vulnerability/CVE-2026-33794

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-33794/
Summaries are generated and may contain mistakes; the official description above is the record.