Paper/Archive/CVE-2026-80155

CVE-2026-80155

LANTRONIX SLC8000 — Lantronix Autonomous Out-of-Band Devices Unauthenticated Authentication Bypass via snprintf Path Truncation

Description · from the CVE record

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

ProductAffectedFixed inSource
SLC8000< 9.7.0.59.7.0.5CNA
EMG8500< 9.7.0.19.7.0.1CNA
EMG7500< 9.7.0.19.7.0.1CNA
SLB882all versions–CNA
SLCx-03all versions–CNA
SLCx-02all versions–CNA
SLC9000< 9.7.0.29.7.0.2CNA

Scores by source

VulnCheck (CNA)10.0CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:H/SC:H/SI:H/SA:H
VulnCheck (CNA)10.0CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:H
CISA ADPSSVCExploitation: none · Automatable: yes · Technical impact: total

References

writeuprevrb.net/2026/09/21/revrb-lantern.htmlpatchts.lantronix.com/ftp/slc8000/9.7.0.5R2patchts.lantronix.com/ftp/emg/EMG_8500/9.7.0.1R2patchts.lantronix.com/ftp/emg/EMG_7500/9.7.0.1R2patchts.lantronix.com/ftp/SLC9000/9.7.0.2R1writeupvulncheck.com/advisories/lantronix-autonomous-out-of-band-devices-unauthenticated-authentication-bypass-via-snprintf-path-truncation