CVE-2026-80156: Path Traversal (CVSS 9.1)

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.

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CVSS v3.1 Score

9.1

CRITICAL

CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:C/C:H/I:H/A:H

EPSS — Exploit Prediction

0.0070

Probability of exploitation

0.52%

Percentile rank

EPSS estimates the probability that this vulnerability will be exploited in the wild within the next 30 days. A higher score means more likely to be exploited.

Weakness Type (CWE)

CWE-22 Path Traversal

References

Other References

https://revrb.net/2026/09/21/revrb-lantern.html https://ts.lantronix.com/ftp/SLC9000/9.7.0.2R1/ https://ts.lantronix.com/ftp/emg/EMG_7500/9.7.0.1R2/ https://ts.lantronix.com/ftp/emg/EMG_8500/9.7.0.1R2/ https://ts.lantronix.com/ftp/slc8000/9.7.0.5R2/ https://www.vulncheck.com/advisories/lantronix-autonomous-out-of-band-devices-arbitrary-file-write-via-upload-filename-validation-bypass

Frequently Asked Questions

What is CVE-2026-80156? +

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. It has a CVSS v3.1 base score of 9.1 (CRITICAL).

How severe is CVE-2026-80156? +

CVE-2026-80156 has a CVSS v3.1 score of 9.1 out of 10, rated CRITICAL. This is a critical vulnerability that should be patched immediately. The EPSS score is 0.0070, placing it in the 1th percentile for exploitation probability.

How do I check if I'm vulnerable to CVE-2026-80156? +

You can use Secably's free Website Scanner to check your website for known vulnerabilities. For infrastructure scanning, use the Port Scanner to identify exposed services that may be affected. Check the vendor advisories linked above for specific patch and version information.

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