All firmware versions of Lantronix SLC8000, SLC9000, EMG8500, EMG7500, SLB882, SLCx-03, and SLCx-02 contain an authentication bypass vulnerability in the web management portal that allows unauthenticated attackers to derive valid session tokens of logged-in users and bypass source IP and User-Agent validation. Session tokens are generated deterministically from the device model and the current time at one-second resolution, resulting in a small enumerable set of possible active tokens. Attackers can construct a crafted URI that exploits file extension handling in the web server path routing to bypass per-session source-address validation, then use a derived token from a different source address to gain elevated privileges on the affected device and potentially impact downstream serial-attached devices.
Published: 2026-09-22
Updated: 2026-09-24
Base Score: 10
Vector: CVSS2#AV:N/AC:L/Au:N/C:C/I:C/A:C
Severity: Critical
Base Score: 9.6
Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:H/I:H/A:H
Severity: Critical
Base Score: 8.9
Vector: CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:A/VC:H/VI:H/VA:H/SC:H/SI:H/SA:H
Severity: High
EPSS: 0.00627