CVE-2026-33797 PUBLISHED

Junos OS and Junos OS Evolved: An attacker sending a specific genuine BGP packet causes a BGP reset

Assigner: juniper
Reserved: 23.03.2026 Published: 09.04.2026 Updated: 09.04.2026

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 doesn't not affected Junos OS versions before 25.2R1.

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

This issue doesn't not affected Junos OS Evolved versions before 25.2R1-EVO.

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

Metrics

CVSS Vector: CVSS:4.0/AV:A/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:L/AU:Y/R:A/V:C/RE:M/U:Green
CVSS Score: 7.1

Product Status

Vendor Juniper Networks
Product Junos OS
Versions Default: unaffected
  • affected from 25.2 to 25.2R2 (excl.)
  • unaffected from 0 to 25.2R1 (excl.)
Vendor Juniper Networks
Product Junos OS Evolved
Versions Default: unaffected
  • affected from 25.2 to 25.2R2-EVO (excl.)
  • unaffected from 0 to 25.2R1-EVO (excl.)

Affected Configurations

[ protocols bgp group <group> neighbor ]

Exploits

Juniper SIRT is not aware of any malicious exploitation of this vulnerability.

Workarounds

There are no known workarounds for this issue.

Solutions

The following software releases have been updated to resolve this specific issue: Junos OS: 25.2R2, 25.4R1, and all subsequent releases. Junos OS Evolved: 25.2R2-EVO, 25.4R1-EVO, and all subsequent releases.

References

Problem Types

  • CWE-20 Improper Input Validation CWE