CVE-2026-102178

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Stack-Based Buffer Overflow in Juniper Junos OS BGP Flowspec

Publication date: 2026-10-14

Last updated on: 2026-10-16

Assigner: Juniper Networks, Inc.

Description

A Stack-based Buffer Overflow vulnerability in the BGP routing daemon of Juniper Networks Junos OS and Junos OS Evolved allows a configured BGP flowspec peer to cause routing-engine compromise or a routing-daemon denial of service via flowspec route re-advertisement when BGP update-threading is enabled.

CVSS Scores

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Meta Information

Published

2026-10-14

Last Modified

2026-10-16

Generated

2026-10-19

AI Q&A

2026-10-15

EPSS Evaluated

2026-10-18

NVD

CVE-2026-102178

EUVD

EUVD-2026-101394

Affected Vendors & Products

Vendor	Product	Version / Range
Juniper	Networks	Junos OS 0
Juniper	Networks	Junos OS 23.4
Juniper	Networks	Junos OS 24.2
Juniper	Networks	Junos OS 24.4
Juniper	Networks	Junos OS 25.2
Juniper	Networks	Junos OS 25.4
Juniper	Networks	Junos OS 26.2
Juniper	Networks	Junos OS Evolved 0
Juniper	Networks	Junos OS Evolved 23.4
Juniper	Networks	Junos OS Evolved 24.2
Juniper	Networks	Junos OS Evolved 24.4
Juniper	Networks	Junos OS Evolved 25.2
Juniper	Networks	Junos OS Evolved 25.4
Juniper	Networks	Junos OS Evolved 26.2
Juniper	Networks	Junos OS Evolved 23.4X100
Juniper	Networks	Junos OS Evolved 25.2X100
Juniper	Networks	Junos OS Evolved 25.4X300

Helpful Resources

Exploitability

CWE

KEV

CWE ID	Description
CWE-121	A stack-based buffer overflow condition is a condition where the buffer being overwritten is allocated on the stack (i.e., is a local variable or, rarely, a parameter to a function).

Attack-Flow Graph

Executive Summary

This vulnerability is a stack-based buffer overflow in the BGP routing daemon of Juniper Networks Junos OS and Junos OS Evolved. It allows a configured BGP flowspec peer to cause routing-engine compromise or a routing-daemon denial of service by re-advertising flowspec routes when BGP update-threading is enabled.

Detection Guidance

Detecting this vulnerability requires checking for vulnerable Juniper Junos OS/Junos OS Evolved versions and BGP flowspec configurations. Inspect BGP daemon logs for flowspec route re-advertisement anomalies or crashes. Monitor routing-engine stability and BGP update-threading status. Juniper recommends reviewing system logs for unexpected routing daemon restarts or memory corruption errors.

Impact Analysis

An attacker could exploit this to crash the routing daemon or take control of the routing engine, leading to network disruption or unauthorized access. This could result in loss of network connectivity, data breaches, or service outages.

Compliance Impact

This vulnerability allows a remote attacker to cause a denial of service or compromise the routing engine, which could disrupt network operations. Such disruptions may lead to unauthorized access, data breaches, or service unavailability, potentially violating compliance requirements under GDPR (data protection) and HIPAA (healthcare data security) due to compromised system integrity and availability.

Mitigation Strategies

Disable BGP update-threading on affected Juniper Junos OS and Junos OS Evolved devices. Disable BGP flowspec peering if not required. Apply vendor patches immediately when available.

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