CVE-2026-21908Junos OS and Junos OS Evolved: Use after free vulnerability In 802.1X authentication daemon can cause crash of the dot1xd process
Updated under an hour ago ()
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It affects Juniper Networks Junos OS and 3 other products. Add what you run to find out whether that includes you.
No exploitation reported and no EPSS estimate yet.
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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
- 7.1 HIGH (v3.1, CNA)CVSS:3.1/AV:A/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:H
- Weakness (CWE)
- CWE-416
- Known exploited
- Not in CISA's KEV catalog
- EPSS (exploitation in the next 30 days)
- Not loaded for this CVE
- Assigned by
- juniper
- NVD analysis
- Analyzed
- Record last updated
- Feb 26, 2026
- First seen by InfoSec Signals
- Oct 9, 2026
The CVE record on cve.org NVD's entry
The CVE record is authoritative. Products marked “from the name” were identified from the CNA's free-text names, not a CPE, and are matched less certainly. This product uses the NVD API but is not endorsed or certified by the NVD.