CVE-2026-80155
Received Received - Intake

Authentication Bypass in Lantronix Web Management Portal

Publication date: 2026-09-22

Last updated on: 2026-09-22

Assigner: VulnCheck

Description
Lantronix SLC8000 before firmware v9.7.0.5, 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.

CVSS Scores

EPSS Scores

Probability:
Percentile:

Meta Information

Published
2026-09-22
Last Modified
2026-09-22
Generated
2026-09-22
AI Q&A
2026-09-22
EPSS Evaluated
N/A
NVD
CVE-2026-80155
EUVD
EUVD-2026-84521

Affected Vendors & Products

Showing 6 associated CPEs
Vendor Product Version / Range
lantronix slc8000 to 9.7.0.5 (exc)
lantronix emg8500 to 9.7.0.1 (exc)
lantronix emg7500 to 9.7.0.1 (exc)
lantronix slb882 *
lantronix slcx-03 *
lantronix slcx-02 *

Helpful Resources

Exploitability

CWE
CWE Icon
KEV
KEV Icon
CWE ID Description
CWE-22 The product uses external input to construct a pathname that is intended to identify a file or directory that is located underneath a restricted parent directory, but the product does not properly neutralize special elements within the pathname that can cause the pathname to resolve to a location that is outside of the restricted directory.

Attack-Flow Graph

AI Quick Actions

Instant insights powered by AI
Executive Summary

This is a critical authentication bypass vulnerability in Lantronix Autonomous Out-of-Band devices. It allows unauthenticated attackers to bypass login checks by exploiting path truncation in the web management portal's session cookie handling. The flaw occurs due to improper use of snprintf with a fixed-size buffer, enabling path traversal to redirect authentication to arbitrary files like the user database. This grants access to read sensitive configuration files and upload malicious files, leading to remote code execution and full device compromise.

Detection Guidance

Detect this vulnerability by checking firmware versions of Lantronix devices. Affected versions include SLC8000 before v9.7.0.5, EMG8500/EMG7500 before v9.7.0.1, and all versions of SLB882/SLCx-03/SLCx-02. Scan for unauthorized file uploads or suspicious session cookie manipulation in web management portals.

Impact Analysis

Attackers can completely take over affected devices, stealing sensitive data, installing malware, or disrupting operations. Since these devices often manage serial-connected systems, the impact may extend to connected industrial equipment or networks. The vulnerability enables full loss of confidentiality, integrity, and availability on the device and potentially downstream systems.

Compliance Impact

This vulnerability likely violates compliance requirements for data protection and access controls in standards like GDPR and HIPAA. It enables unauthorized access to sensitive data (e.g., user credentials, configurations) and allows modification of system files, which could lead to breaches of confidentiality and integrity mandates. Organizations using affected devices may face compliance violations and regulatory penalties.

Mitigation Strategies

Immediately update affected Lantronix devices to patched firmware versions: SLC8000 to v9.7.0.5, EMG8500/EMG7500 to v9.7.0.1. Isolate vulnerable devices from critical networks until patched. Monitor for unauthorized access or file uploads.

Chat Assistant

Ask questions about this CVE
Hi! I’m here to help you understand CVE-2026-80155. Ask me anything about the vulnerability, its impact, or mitigation strategies.
0/70

EPSS Chart