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Vulnerability Intelligence Report
Lantronix G520 Series Cellular Gateway Improper Verification of Cryptographic Signature

CVE-2026-91191

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.

No Active Exploit Signals
CVSS Base Score
7.5
HIGH
Exploitability:1.7
Impact Score:5.9
EPSS Probability:0.21%
Executive Threat Verdict
Evaluating...
Evaluating Threat Landscape...
Assessing known weaponization, exploitation telemetry, and federal advisories.
Attack Surface
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Authentication
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Weaponization
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SSVC Action
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Weaknesses (CWE)

Affected Products & Versions

Vendor Product Affected Versions
Lantronix G520 Series 2.6.0.4R6 stable (affected)

References & Technical Advisories

No reference links found.

Threat Intelligence Signals

EPSS Score
0.209%

Identity & Timeline

StatusPUBLISHED
Assigning AuthorityCybersecurity and Infrastructure Security Agency (CISA) Industrial Control Systems (ICS) · CERT · USA
Reserved2026-09-17T19:24:31
Published2026-09-29T21:04:52
Last Updated2026-09-30T15:28:15

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