CVE-2026-91191

Lantronix G520 Series Cellular Gateway Improper Verification of Cryptographic Signature

Published Sep 29, 2026 CVSS 4.0 · 7.7 High EPSS < 1% KEV · Not listed
Description
The device's update mechanism includes conditions that allow unauthorized software packages to be accepted as authentic. During the boot process, the stock done function disables signature verification in the OPKG configuration before restoring optional packages from a writable, unsigned feed. Separately, the publicly distributed SDK contains the production private key whose corresponding public key is trusted by both stable and beta firmware builds. Either issue undermines package authenticity, and together they allow an attacker to provide packages that appear valid to the system. Even if signature enforcement is restored, the exposed production key enables an attacker to generate signatures that the device will continue to trust. An attacker who can supply a malicious package may be able to execute arbitrary code with root privileges during installation.

Remediation

Vendor Solution

Lantronix has addressed the reported issues with release version 2.6.0.7R6 which is available on their website. https://ltrxdev.atlassian.net/wiki/spaces/LTRXTS/pages/1889828865/Latest+firmware+for+the+G520+Series+G526+G526RP+G527+G528 For more information, see the Lantronix Vulnerability Library. https://www.lantronix.com/technical-support/security-updates/vulnerability-disclosure-policy/vulnerability-library/ For more information or technical assistance, contact Lantronix support: Support@lantronix.com mailto:Support@lantronix.com

Tracking

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Advisories

No advisories available
History
Type Values Removed Values Added
First Time appeared Lantronix
Lantronix g520 Series
Vendors & Products Lantronix
Lantronix g520 Series
Type Values Removed Values Added
Metrics ssvc

{'options': {'Automatable': 'no', 'Exploitation': 'none', 'Technical Impact': 'total'}, 'version': '2.0.3'}

Type Values Removed Values Added
Description The device's update mechanism includes conditions that allow unauthorized software packages to be accepted as authentic. During the boot process, the stock done function disables signature verification in the OPKG configuration before restoring optional packages from a writable, unsigned feed. Separately, the publicly distributed SDK contains the production private key whose corresponding public key is trusted by both stable and beta firmware builds. Either issue undermines package authenticity, and together they allow an attacker to provide packages that appear valid to the system. Even if signature enforcement is restored, the exposed production key enables an attacker to generate signatures that the device will continue to trust. An attacker who can supply a malicious package may be able to execute arbitrary code with root privileges during installation.
Title Lantronix G520 Series Cellular Gateway Improper Verification of Cryptographic Signature
Weaknesses CWE-347
References
Metrics cvssV3_1

{'score': 7.5, 'vector': 'CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:U/C:H/I:H/A:H'}

cvssV4_0

{'score': 7.7, 'vector': 'CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:P/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N'}

Weaknesses

Sources

Status
PUBLISHED
Assigner
icscert
Published
Updated
Sep 30, 2026, 3:28 PM
Reserved
Sep 17, 2026, 7:24 PM
Status
Awaiting Analysis
Published
Sep 29, 2026, 10:19 PM
Modified
Sep 30, 2026, 4:46 PM