Home/CVE/An Improper Input Validation vulnerability in Juniper Networks Junos OS and Junos OS Evolved allows an unauthenticated,
CVE

CVE-2026-33797

An Improper Input Validation vulnerability in Juniper Networks Junos OS and Junos OS Evolved allows an unauthenticated,

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.

HIGH · CVSS 7.4 EPSS 0.00039
Schedule remediation
  • CVSS base score ≥ 7.0
Sigma rules0 YARA rules0
⬡

Weakness Classification

CWE-20Improper Input Validation
▤

Affected Products & Versions

2
juniper junosall versions
juniper junos os evolvedall versions
▣

Scoring & Timeline

7.4
HIGH · CVSS v3.1 · sirt@juniper.net
View on NVD
Attack Vector
Network Adjacent Local Physical
Attack Complexity
Low High
Privileges Required
None Low High
User Interaction
None Required
Scope
Unchanged Changed
Confidentiality
None Low High
Integrity
None Low High
Availability
None Low High
Published to NVD09 Apr 2026 · 10:16 PM
CVSS VectorCVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:C/C:N/I:N/A:H
SSVC triage · cisa-vulnrichment
Exploitation
none
Automatable
no
Technical impact
partial
SSVC asks the questions that actually drive patch urgency: is it being exploited, can attacks be automated, and how total is the impact.
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References & Sources

2
Source URLs (vendor pages, mailing lists, write-ups). Exploit/PoC links are in their own section above to avoid duplication.
https://kb.juniper.net/JSA107850Vendor Advisory
https://supportportal.juniper.net/JSA107850
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