CVE-2024-39511: Junos OS: The 802.1X Authentication Daemon crashes on running a specific command

Severity: medium (CVSS 5.5 v3.1)
Exploited in the wild: not listed in CISA KEV
EPSS: 0.1% probability of exploitation in the next 30 days
Public exploit or detection template: none known
Published: 2024-07-10 · updated 2026-06-17
Weakness: CWE-20

Description

An Improper Input Validation vulnerability in the 802.1X Authentication (dot1x) Daemon of Juniper Networks Junos OS allows a local, low-privileged attacker with access to the CLI to cause a Denial of Service (DoS). On running a specific operational dot1x command, the dot1x daemon crashes. An attacker can cause a sustained DoS condition by running this command repeatedly. When the crash occurs, the authentication status of any 802.1x clients is cleared, and any authorized dot1x port becomes unauthorized. The client cannot re-authenticate until the dot1x daemon restarts. This issue affects Junos OS: * All versions before 20.4R3-S10; * 21.2 versions before 21.2R3-S7; * 21.4 versions before 21.4R3-S6; * 22.1 versions before 22.1R3-S5; * 22.2 versions before 22.2R3-S3; * 22.3 versions before 22.3R3-S2; * 22.4 versions before 22.4R3-S1; * 23.2 versions before 23.2R2.

Affected products

Juniper Junos OS: before 20.4; 20.4, 20.4-r1, 20.4-r1-s1, 20.4-r2, 20.4-r2-s1, 20.4-r2-s2 (+80) — fixed in 20.4

How to fix

Upgrade to a fixed version: Juniper Junos OS 20.4. Check the vendor advisory for mitigations.

References

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