CVE-2026-21908

7.1 HIGH
Published: January 15, 2026 Modified: January 23, 2026
View on NVD

Description

A Use After Free vulnerability was identified in the 802.1X authentication daemon (dot1xd) of Juniper Networks Junos OS and Junos OS Evolved that could allow an authenticated, network-adjacent attacker flapping a port to crash the dot1xd process, leading to a Denial of Service (DoS), or potentially execute arbitrary code within the context of the process running as root. The issue is specific to the processing of a change in authorization (CoA) when a port bounce occurs. A pointer is freed but was then referenced later in the same code path. Successful exploitation is outside the attacker's direct control due to the specific timing of the two events required to execute the vulnerable code path. This issue affects systems with 802.1X authentication port-based network access control (PNAC) enabled. This issue affects: Junos OS:  * from 23.2R2-S1 before 23.2R2-S5,  * from 23.4R2 before 23.4R2-S6,  * from 24.2 before 24.2R2-S3,  * from 24.4 before 24.4R2-S1,  * from 25.2 before 25.2R1-S2, 25.2R2;  Junos OS Evolved:  * from 23.2R2-S1 before 23.2R2-S5-EVO,  * from 23.4R2 before 23.4R2-S6-EVO,  * from 24.2 before 24.2R2-S3-EVO,  * from 24.4 before 24.4R2-S1-EVO,  * from 25.2 before 25.2R1-S2-EVO, 25.2R2-EVO.

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CVSS v3.x Details

0.0 Low Medium High Critical 10.0
Vector String
CVSS:3.1/AV:A/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:H

References to Advisories, Solutions, and Tools

Patch Vendor Advisory Exploit Third Party Advisory
https://kb.juniper.net/JSA106007
Source: sirt@juniper.net
Vendor Advisory
https://supportportal.juniper.net/JSA106007
Source: sirt@juniper.net
Vendor Advisory

2 reference(s) from NVD

Quick Stats

CVSS v3 Score
7.1 / 10.0
EPSS (Exploit Probability)
0.0%
2th percentile
Exploitation Status
Not in CISA KEV

Weaknesses (CWE)

Affected Vendors

juniper