What’s Vulnerable › Vulnerabilities
CVE-2026-102178: Junos OS and Junos OS Evolved: When BGP update-threading is enabled a specifically malformed flowspec NLRI causes routing-engine compromise
- Severity: critical (CVSS 9.8 v3.1)
- Exploited in the wild: not listed in CISA KEV
- EPSS: 0.5% probability of exploitation in the next 30 days
- Public exploit or detection template: none known
- Published: 2026-10-14 · updated 2026-10-16
- Weakness: CWE-121
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.
Affected products
- Juniper Junos OS: before 23.2R2-S7.7; from 23.4 before 23.4R2-S8.13; from 24.2 before 24.2R2-S5.5; from 24.4 before 24.4R2-S5; from 25.2 before 25.2R2-S2; from 25.4 before 25.4R1-S3 — fixed in 23.2R2-S7.7, 23.4R2-S8.13, 24.2R2-S5.5, 24.4R2-S5, 25.2R2-S2, 25.4R1-S3
- Juniper Networks Junos OS Evolved: before 23.2R2-S7.7-EVO; from 23.4 before 23.4R2-S8.11-EVO; from 24.2 before 24.2R2-S5.6-EVO; from 24.4 before 24.4R2-S5-EVO; from 25.2 before 25.2R2-S2-EVO; from 25.4 before 25.4R1-S3-EVO — fixed in 23.2R2-S7.7-EVO, 23.4R2-S8.11-EVO, 24.2R2-S5.6-EVO, 24.4R2-S5-EVO, 25.2R2-S2-EVO, 25.2X100-D35-EVO
How to fix
Upgrade to a fixed version: Juniper Junos OS 23.2R2-S7.7, 23.4R2-S8.13, 24.2R2-S5.5, 24.4R2-S5; Juniper Networks Junos OS Evolved 23.2R2-S7.7-EVO, 23.4R2-S8.11-EVO, 24.2R2-S5.6-EVO, 24.4R2-S5-EVO. Check the vendor advisory for mitigations.
References
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