Vulnerability · Published Sep 22, 2026 · Assigned by VulnCheck
CVE-2026-80155Lantronix Autonomous Out-of-Band Devices Unauthenticated Authentication Bypass via snprintf Path Truncation
Critical 10.0
In plain English
A critical-severity path traversal in EMG7500 from LANTRONIX. There are no confirmed reports of exploitation so far. The chance it is exploited in the next 30 days is estimated at 1.0% (higher than 64% of all known vulnerabilities).
Official 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 an authentication bypass vulnerability in the web management portal upload endpoint that allows unauthenticated attackers to read sensitive configuration files and upload files to arbitrary filesystem locations, leading to remote code execution. The web configuration server constructs the session cookie file path using snprintf with a fixed-size buffer; by supplying a cookie value of a specific length an attacker causes the path to truncate at the required delimiter and leverages path traversal to redirect authentication validation to an arbitrary on-disk file such as the local user database, bypassing all session checks. 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 (as reported)
Weakness: CWE-22 · Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:H
References
- Researcher Disclosure technical-description
- SLC8000 Firmware patch
- EMG8500 Firmware patch
- EMG7500 Firmware patch
- SLC9000 Firmware patch
- https://www.vulncheck.com/advisories/lantronix-autonomous-out-of-band-devices-unauthenticated-authentication-bypass-via-snprintf-path-truncation third-party-advisory