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.
Metrics
Affected Vendors & Products
No advisories yet.
Solution
The following software releases have been updated to resolve this specific issue: Junos OS 23.2R2-S5, 23.4R2-S6, 24.2R2-S3, 24.4R2-S1, 25.2R1-S2, 25.2R2, 25.4R1, and all subsequent releases. Junos OS Evolved: 23.2R2-S5-EVO, 23.4R2-S6-EVO, 24.2R2-S3-EVO, 24.4R2-S1-EVO, 25.2R1-S2-EVO, 25.2R2-EVO, 25.4R1-EVO,
Workaround
There are no known workarounds for this issue.
Thu, 15 Jan 2026 21:15:00 +0000
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| Metrics |
ssvc
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Thu, 15 Jan 2026 20:30:00 +0000
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| 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. | |
| Title | Junos OS and Junos OS Evolved: Use after free vulnerability In 802.1X authentication daemon can cause crash of the dot1xd process | |
| Weaknesses | CWE-416 | |
| References |
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| Metrics |
cvssV3_1
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Projects
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Status: PUBLISHED
Assigner: juniper
Published:
Updated: 2026-01-15T20:45:07.011Z
Reserved: 2026-01-05T17:32:48.710Z
Link: CVE-2026-21908
Updated: 2026-01-15T20:45:01.036Z
Status : Received
Published: 2026-01-15T21:16:06.537
Modified: 2026-01-15T21:16:06.537
Link: CVE-2026-21908
No data.
OpenCVE Enrichment
No data.