CVE-2026-80155

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.

Overview

State: PUBLISHED
Assigner (CNA): VulnCheck
CVSS severity: CRITICAL
CVSS score: 10.0 / 10
CVSS vector: CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:H/SC:H/SI:H/SA:H
Effective score: 10.0 / 10 CRITICAL source: CNA overview
CWE(s): CWE-22
Reserved: 2026-08-25
Published: 2026-09-22 15:22 UTC
Last updated: 2026-09-22 15:43 UTC
Source: https://raw.githubusercontent.com/CVEProject/cvelistV5/main/cves/2026/80xxx/CVE-2026-80155.json
Linked Threat: CVE-2026-80155 — Lantronix Autonomous Out-of-Band Devices Unauthenticated Authentication Bypass via snprintf Path Truncation

NVD triage scoring NVD CVE 2.0

Layer NVD adds on top of the CNA's CVE record — published / last-modified timestamps, exploitability / impact subscores, and the FIRST.org EPSS probability that this CVE will be exploited in the wild in the next 30 days.

NVD published: 2026-09-22 16:18:01 UTC
NVD last modified: 2026-09-22 20:25:55 UTC
NVD CVSS v3.1: 10.0 / 10 CRITICAL source: disclosure@vulncheck.com
NVD CVSS vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:H
Exploitability subscore: 3.9 / 10
Impact subscore: 6.0 / 10

European Union Vulnerability Database ENISA EUVD

ENISA's official EU repository for curated vulnerability intelligence. Carries a separate identifier (EUVD-YYYY-NNNN) and frequently exposes an earlier-published description + CVSS than NVD does.

EUVD ID: EUVD-2026-84521
Assigner: VulnCheck
Published: Sep 22, 2026, 3:22:57 PM
Updated: Sep 22, 2026, 3:43:00 PM
EUVD base score (CVSS 4.0): 10.0 / 10
CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:H/SC:H/SI:H/SA:H
EUVD-reported EPSS: 0.0000
Vendors: Lantronix
Products: SLCx-02 (*)

EMG8500 (0 <9.7.0.1)

SLB882 (*)

EMG7500 (0 <9.7.0.1)

SLCx-03 (*)

SLC8000 (0 <9.7.0.5)
Aliases: GHSA-h7c7-c453-99x2

ENISA 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.

EUVD references (5)

Affected products (6)

Vendor	Product	Versions	Platforms
LANTRONIX	SLC8000	`0` (affected)	—
LANTRONIX	EMG8500	`0` (affected)	—
LANTRONIX	EMG7500	`0` (affected)	—
LANTRONIX	SLB882	`*` (affected)	—
LANTRONIX	SLCx-03	`*` (affected)	—
LANTRONIX	SLCx-02	`*` (affected)	—

Vendor references (5)

References embedded in the original CVE record by the assigning CNA.

Researcher Disclosure technical-description
SLC8000 Firmware patch
EMG8500 Firmware patch
EMG7500 Firmware patch
https://www.vulncheck.com/advisories/lantronix-autonomous-out-of-band-devices-unauthenticated-authentication-bypass-via-snprintf-path-truncation third-party-advisory

Web references (0)

DuckDuckGo results ranked by threat-intel / vendor advisory domains. Generated by the 🔎 Find references (web) button above — same flow as the Remediations search.

No web references attached yet.

NVD-tagged references (5)

Reference list NVD curates from the CNA record, vendor advisories, and third-party reports. The tag chips below are NVD's analyst-assigned categories.

https://revrb.net/2026/09/21/revrb-lantern.html disclosure@vulncheck.com
https://ts.lantronix.com/ftp/emg/EMG_7500/9.7.0.1R2/ disclosure@vulncheck.com
https://ts.lantronix.com/ftp/emg/EMG_8500/9.7.0.1R2/ disclosure@vulncheck.com
https://ts.lantronix.com/ftp/slc8000/9.7.0.5R2/ disclosure@vulncheck.com
https://www.vulncheck.com/advisories/lantronix-autonomous-out-of-band-devices-unauthenticated-authentication-bypass-via-snprintf-path-truncation disclosure@vulncheck.com

Remediations (10)

Remediations are stored against the linked Threat row; the list below is deduplicated across both pages.

CVE-2026-80155: Lantronix Path Traversal (CVSS 10) | CVETodo

web:cvetodo.com

CVE-2026-80155 is a CVSS 10 Path Traversal vulnerability in Lantronix SLC8000, EMG8500, EMG7500. See exploitation status, patch guidance, and technical details.

2026-09-23 15:14 UTC
Cisco Advance Notification for Publication of September 16, 2026 ...

web:sec.cloudapps.cisco.com

On September 16, 2026 , the Cisco Product Security Incident Response Team (PSIRT) published the advisories that are listed in the following tables. To remediate these vulnerabilities, Cisco strongly recommends that customers upgrade to the fixed software that is indicated in the advisories. For more information about changes in Cisco PSIRT vulnerability disclosure, see Strengthening the ...

2026-09-23 15:14 UTC
Microsoft Patch Tracker (September 2026): Exploit-Ranked | Senserva

web:senserva.com

Every Microsoft security patch (KB) and the CVEs it fixes, with severity, CVSS, and CISA KEV status. Cross-linked to the CVE reference.

2026-09-23 15:14 UTC
July 18, 2026—Hotpatch KB5121768 (OS Builds 26200.8893 and 26100.8893 ...

web:support.microsoft.com

This out-of-band (OOB) update for Windows 11, version 25H2 and Windows 11, version 24H2 (KB5121768) is cumulative. It includes all improvements from previous security and non-security updates, along with an additional fix . Improvements This OOB update includes the following improvement: [System Performance] This update addresses an issue affecting a limited number of devices with an Intel ...

2026-09-23 15:14 UTC
Critical Patches Issued for Microsoft Products, August 11, 2026

web:www.cisecurity.org

<p>Multiple vulnerabilities have been discovered in Microsoft products, the most severe of which could allow for remote code execution. Successful exploitation of the most severe of these vulnerabilities could result in an attacker gaining the same privileges as the logged-on user. Depending on the privileges associated with the user, an attacker could then install programs; view, change, or ...

2026-09-23 15:14 UTC
Security Vulnerabilities fixed in Firefox 155 — Mozilla

web:www.mozilla.org

Mozilla Foundation Security Advisory 2026 -82 Security Vulnerabilities fixed in Firefox 155 Announced September 1, 2026 Impact high Products Firefox Fixed in Firefox 155 # CVE - 2026 -84117: Privilege escalation in Firefox for Android Reporter HiWorld Impact high References Bug 2053320 # CVE - 2026 -84118: Use-after-free in the JavaScript: GC component Reporter x0e Impact high References Bug 2057457 ...

2026-09-23 15:14 UTC
Oracle Critical Patch Update Advisory - April 2026

web:www.oracle.com

This Critical Patch Update contains 481 new security patches across the product families listed below. Please note that an MOS note summarizing the content of this Critical Patch Update and other Oracle Software Security Assurance activities is located at April 2026 Critical Patch Update: Executive Summary and Analysis.

2026-09-23 15:14 UTC
Oracle Critical Patch Update Advisory - July 2026

web:www.oracle.com

This Critical Patch Update contains 1448 new security patches across the product families listed below. Please note that a My Oracle Support (MOS) note summarizing the content of this Critical Patch Update and other Oracle Software Security Assurance activities is located at July 2026 Critical Patch Update: Executive Summary and Analysis.

2026-09-23 15:14 UTC
July 2026 Patch Tuesday: Largest Patch Tuesday 569 CVEs - Tenable

web:www.tenable.com

Microsoft patched 569 CVEs in July 2026 , the largest Patch Tuesday release in its history. 56 critical CVEs patched including three zero-day vulnerabilities.

2026-09-23 15:14 UTC
Patch Tuesday September 2026: Security Updates & CVE Analysis

web:zecurit.com

Get the complete breakdown of Microsoft's September 2026 Patch Tuesday. We analyze the latest security updates and all critical CVEs .

2026-09-23 15:14 UTC

AI Forensic Analysis

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Raw JSON

The full cvelistV5 record. Download as CVE-2026-80155.json.

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