CVE-2026-21908

HIGH EPSS 21.0%
Published Jan 15, 20265mo ago · Modified Jun 17, 20262w ago
7.5 CVSS 4.0
High
Find Similar
Published Jan 15, 2026 5mo ago
Last Modified Jun 17, 2026 2w ago

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.

CVSS Details

Base Score
7.5
Exploitability
Impact
Vector string
CVSS:4.0/AV:A/AC:L/AT:P/PR:L/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:L/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:M/U:Green
Attack Vector Adjacent
Attack Complexity Low
Privileges Required Low
User Interaction None
Scope X

Threat Intelligence

EPSS Exploit Probability
21.0% percentile
Exploit & Patch Status
No Known Exploit
No Patch Available

Weaknesses 1

CWE-416 Use After Free Memory Safety

Affected Products 51

VendorProductVersionRange
juniperjunos23.2any
juniperjunos23.2any
juniperjunos23.2any
juniperjunos23.2any
juniperjunos23.4any
juniperjunos23.4any
juniperjunos23.4any
juniperjunos23.4any
juniperjunos23.4any
juniperjunos23.4any
juniperjunos24.2any
juniperjunos24.2any
juniperjunos24.2any
juniperjunos24.2any
juniperjunos24.2any
juniperjunos24.2any
juniperjunos24.2any
juniperjunos24.4any
juniperjunos24.4any
juniperjunos24.4any
juniperjunos24.4any
juniperjunos24.4any
juniperjunos25.2any
juniperjunos25.2any
juniperjunos25.2any
juniperjunos25.2any
juniperjunos_os_evolved23.2any
juniperjunos_os_evolved23.2any
juniperjunos_os_evolved23.2any
juniperjunos_os_evolved23.2any
juniperjunos_os_evolved23.4any
juniperjunos_os_evolved23.4any
juniperjunos_os_evolved23.4any
juniperjunos_os_evolved23.4any
juniperjunos_os_evolved23.4any
juniperjunos_os_evolved23.4any
juniperjunos_os_evolved24.2any
juniperjunos_os_evolved24.2any
juniperjunos_os_evolved24.2any
juniperjunos_os_evolved24.2any
juniperjunos_os_evolved24.2any
juniperjunos_os_evolved24.2any
juniperjunos_os_evolved24.4any
juniperjunos_os_evolved24.4any
juniperjunos_os_evolved24.4any
juniperjunos_os_evolved24.4any
juniperjunos_os_evolved24.4any
juniperjunos_os_evolved25.2any
juniperjunos_os_evolved25.2any
juniperjunos_os_evolved25.2any
juniperjunos_os_evolved25.2any

References 2

Remediation

No remediation data recorded yet

Check vendor advisories and the NVD entry for patch availability.