# CVE-2026-33797: An Improper Input Validation vulnerability in Juniper Networks Junos OS and Junos OS Evolved allows an…

Source: https://junglewise.ai/threats/cve-2026-33797-an-improper-input-validation-vulnerability-in-juniper-networks  
Publisher: Junglewise Threat Intelligence, https://junglewise.ai/threats  
Published: 2026-04-09  
License: CC BY 4.0 with a link back

CVE-2026-33797 · Severity: high · CVSS 7.4 · Published 2026-04-09

An Improper Input Validation vulnerability in Juniper Networks Junos OS and Junos OS Evolved allows an unauthenticated, adjacent attacker, sending a specific genuine BGP packet in an already established BGP session to reset only that session causing a Denial of Service (DoS).

An attacker repeatedly sending the packet will sustain the Denial of Service (DoS).This issue affects Junos OS:

  *  25.2 versions before 25.2R2


This issue does not affect Junos OS versions before 25.2R1.

This issue affects Junos OS Evolved: 
  *  25.2-EVO versions before 25.2R2-EVO


This issue does not affect Junos OS Evolved versions before 25.2R1-EVO.

eBGP and iBGP are affected.
IPv4 and IPv6 are affected.

Technologies: [Juniper Junos](https://junglewise.ai/threats/technologies/junos), [Juniper Junos Os Evolved](https://junglewise.ai/threats/technologies/juniper-junos-os-evolved). Vendors: [Juniper](https://junglewise.ai/threats/vendors/juniper).

## Quick answers

**Is CVE-2026-33797 exploited in the wild?** No. Junglewise Threat Intelligence has no report of CVE-2026-33797 being exploited in the wild.

**How severe is CVE-2026-33797?** High severity, with a CVSS score of 7.4, published 9 April 2026.

**Which products and versions are affected?** Juniper Junos, Juniper Junos Os Evolved. The advisory does not name versions.

**Is there a fix for CVE-2026-33797?** No fixed version is recorded yet. Check the vendor's advisory in the references below. If you run it, Junglewise drafts a mitigation that fits your setup and applies it once you approve, with senior security engineers behind it.

**Am I affected by CVE-2026-33797?** Check whether you run Juniper Junos or Juniper Junos Os Evolved. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.

## Affected products

- Juniper Junos
- Juniper Junos Os Evolved

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