CVE-2026-33797

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

Published Apr 9, 2026 CVSS 4.0 · 7.1 High EPSS < 1% KEV · Not listed
Description
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.

Remediation

Vendor Solution

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.


Vendor Workaround

There are no known workarounds for this issue.

Tracking

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Advisories

No advisories available
History
Type Values Removed Values Added
Description 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. 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.
References
Type Values Removed Values Added
First Time appeared Juniper
Juniper junos
Juniper junos Os Evolved
CPEs cpe:2.3:o:juniper:junos:25.2:-:*:*:*:*:*:*
cpe:2.3:o:juniper:junos:25.2:r1-s1:*:*:*:*:*:*
cpe:2.3:o:juniper:junos:25.2:r1-s2:*:*:*:*:*:*
cpe:2.3:o:juniper:junos:25.2:r1:*:*:*:*:*:*
cpe:2.3:o:juniper:junos_os_evolved:25.2:-:*:*:*:*:*:*
cpe:2.3:o:juniper:junos_os_evolved:25.2:r1-s1:*:*:*:*:*:*
cpe:2.3:o:juniper:junos_os_evolved:25.2:r1-s2:*:*:*:*:*:*
cpe:2.3:o:juniper:junos_os_evolved:25.2:r1:*:*:*:*:*:*
Vendors & Products Juniper
Juniper junos
Juniper junos Os Evolved
Type Values Removed Values Added
Metrics ssvc

{'options': {'Automatable': 'no', 'Exploitation': 'none', 'Technical Impact': 'partial'}, 'version': '2.0.3'}

Type Values Removed Values Added
First Time appeared Juniper Networks
Juniper Networks junos Os
Juniper Networks junos Os Evolved
Vendors & Products Juniper Networks
Juniper Networks junos Os
Juniper Networks junos Os Evolved
Type Values Removed Values Added
Description 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.
Title Junos OS and Junos OS Evolved: An attacker sending a specific genuine BGP packet causes a BGP reset
Weaknesses CWE-20
References
Metrics cvssV3_1

{'score': 7.4, 'vector': 'CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:C/C:N/I:N/A:H'}

cvssV4_0

{'score': 7.1, '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'}

Weaknesses

Sources

Status
PUBLISHED
Assigner
juniper
Published
Updated
Apr 23, 2026, 8:08 PM
Reserved
Mar 23, 2026, 7:46 PM
Status
Modified
Published
Apr 9, 2026, 10:16 PM
Modified
Oct 26, 2026, 10:10 PM