CVE-2026-80156: Lantronix Autonomous Out-of-Band Devices Arbitrary File Write via Upload Filename Validation Bypass

Severity: critical (CVSS 9.1 v3.1)
Exploited in the wild: not listed in CISA KEV
EPSS: 0.7% probability of exploitation in the next 30 days
Public exploit or detection template: none known
Published: 2026-09-22 · updated 2026-09-24
Weakness: CWE-22

Description

Lantronix SLC8000 before firmware v9.7.0.5, SLC9000 before firmware v9.7.0.2, EMG8500/EMG7500 before firmware v9.7.0.1, and all firmware versions of SLB882/SLCx-03/SLCx-02 contain a path traversal vulnerability in the web management portal upload endpoint that allows authenticated attackers to write arbitrary data to any location on the device's filesystem, leading to remote code execution. The upload filename validation strips backslash characters but does not subsequently check for forward slashes when a backslash is detected; by supplying a filename containing both characters an attacker writes outside the intended upload directory to any writable path. Attackers can use this vulnerability to achieve complete loss of confidentiality, integrity, and availability on the affected device and potentially impact downstream serial-connected devices.

Affected products

LANTRONIX EMG7500: before 9.7.0.1 — fixed in 9.7.0.1
LANTRONIX EMG8500: before 9.7.0.1 — fixed in 9.7.0.1
LANTRONIX SLB882: all versions
LANTRONIX SLC8000: before 9.7.0.5 — fixed in 9.7.0.5
LANTRONIX SLC9000: before 9.7.0.2 — fixed in 9.7.0.2
LANTRONIX SLCx-02: all versions
LANTRONIX SLCx-03: all versions

How to fix

Upgrade to a fixed version: LANTRONIX EMG7500 9.7.0.1; LANTRONIX EMG8500 9.7.0.1; LANTRONIX SLC8000 9.7.0.5; LANTRONIX SLC9000 9.7.0.2. Check the vendor advisory for mitigations.

References

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