CVE-2026-101983: Junos OS and Junos OS Evolved: An attacker causes remote code execution when J-Web virtual-domain is configured

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 2026-10-15
Weakness: CWE-121

Description

A Stack-based Buffer Overflow vulnerability in the httpd process of Juniper Networks Junos OS and Junos OS Evolved allows an unauthenticated network attacker to cause remote code execution and denial of service via a J-Web virtual-domain configured.

Affected products

Juniper Junos OS: 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; from 26.2 before 26.2R1-S2 — fixed in 23.4R2-S8.13, 24.2R2-S5.5, 24.4R2-S5, 25.2R2-S2, 25.4R1-S3, 26.2R1-S2
Juniper Networks Junos OS Evolved: 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; from 26.2 before 26.2R1-S2-EVO — fixed in 23.4R2-S8.11-EVO, 24.2R2-S5.6-EVO, 24.4R2-S5-EVO, 25.2R2-S2-EVO, 25.2X100-D35-EVO, 25.4R1-S3-EVO

How to fix

Upgrade to a fixed version: Juniper Junos OS 23.4R2-S8.13, 24.2R2-S5.5, 24.4R2-S5, 25.2R2-S2; Juniper Networks Junos OS Evolved 23.4R2-S8.11-EVO, 24.2R2-S5.6-EVO, 24.4R2-S5-EVO, 25.2R2-S2-EVO. Check the vendor advisory for mitigations.

References

https://supportportal.juniper.net/JSA112187

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