CVE-2026-33797

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

HIGH
7.4
CVSS Score
Published: April 9, 2026 at 09:31 PM UTC
Updated: June 17, 2026 at 10:38 AM UTC
3 products affected across 2 vendorsJunosJunos OS EvolvedJunos OS Evolved

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Severity
HIGH7.4
Exploit prediction
EPSS 0.2%
SSVC
No known exploit

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.

Affected

Our own answer: ranges merged, affected separated from platform-only, with confidence and review flags.

Vendor states this is fixed in 25.2R1 (unaffected)
Affected range stops below 25.2R2, so it looks safe — our inference, not a vendor statement
25.2 ≤ v < 25.2R2-EVO25.2
Vendor states this is fixed in 25.2R1-EVO (unaffected)
Affected range stops below 25.2R2-EVO, so it looks safe — our inference, not a vendor statement

Remediation

No guide yet

No remediation guidance has been written for this CVE yet. What the record does show:

References (2)

Vendor Advisory
Source: cverecord
https://kb.juniper.net/JSA107850
Vendor Advisory
Source: cverecord
https://supportportal.juniper.net/JSA107850

SSVC — Action Prioritization

SSVCNo known exploitNot automatablePartial impact

SSVC signals action urgency (what to patch first), separate from CVSS which measures severity.

CVSS

7.4HIGHjuniper
Attack Vector
ADJACENT_NETWORK
Complexity
LOW
Privileges
NONE
User Interaction
NONE
Scope
CHANGED
Confidentiality
NONE
Integrity
NONE
Availability
HIGH
Vector?

Quick Info

StatusMODIFIED
CWE
CWE-20

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