# CVE-2026-33803: Junos OS Evolved: A port which has been inadvertently exposed can be reached by an attacker

> An attacker can access an internal process via an exposed port, causing information disclosure and increased CPU usage on Juniper network devices.

- **Severity:** Medium 6.9 (`CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:L/VI:N/VA:L/SC:N/SI:N/SA:N/AU:Y/R:U/RE:M`)
- **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-xc4g-8c26-vcmf

## What is CVE-2026-33803?

CVE-2026-33803 is a medium-severity 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 Restriction of Communication Channel to Intended Endpoints vulnerability in Juniper Networks Junos OS Evolved allows an unauthenticated, network-based attacker to cause a limited information disclosure and availability impact to the device.

Due to a wrong initialization, a process which should only be able to communicate internally within the device can be reached over the network via an open port. This leads to a device being inadvertently exposed and increased CPU cycles spent processing ingress packets.

This issue affects Junos OS Evolved:

  *  all versions before 23.2R2-S7-EVO,
  *  23.4 versions before 23.4R2-S8-EVO,
  *  24.2 versions before 24.2R2-S5-EVO,
  *  24.4 versions before 24.4R2-S4-EVO,
  *  25.2 versions before 25.2R2-S1-EVO,
  *  25.4 versions before 25.4R1-S2-EVO.

Weakness: CWE-923 (Improper Restriction of Communication Channel to Intended Endpoints)

## Which versions are affected by CVE-2026-33803?

It affects 1 product.


Products: Juniper Junos Os Evolved.

## How do I fix CVE-2026-33803?

No fix has been published for CVE-2026-33803 yet. Limit exposure of the affected software until one is available.

## Is CVE-2026-33803 being exploited?

There is no known exploitation of CVE-2026-33803 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-2026-33803 and fix it if it is affected.

What it is: CVE-2026-33803 is a medium-severity 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-2026-33803 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-2026-33803/ (Markdown: https://insights.sbomify.com/CVE-2026-33803/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-33803
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-33803
- OSV: https://osv.dev/vulnerability/CVE-2026-33803

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-33803/
Summaries are generated and may contain mistakes; the official description above is the record.