Lantronix G520 Series Cellular Gateway Improper Verification of Cryptographic Signature
Key facts
- Attack vector
- Network
- Privileges required
- None
- User interaction
- Passive
- Attack complexity
- Low
- Attack requirements
- Present
- Impact type
- Security bypass
- Confidentiality · integrity · availability
- High · High · High
- Fix status
- No fix listed
Attack profile from CVSS 4.0 · CNA. Fix status from CNA. Impact type from CWE-347.
Summary
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.
Why it matters now
SSVC decision points
CISA ADP · SSVC 2.0.3
- Exploitation
- None
- Automatable
- No
- Technical impact
- Total
The decision (Track, Attend, Act) also depends on your mission and well-being impact; see CISA's SSVC guide.
Affected products
Remediation
No fixed version listed by the sources yet.
Timeline
- 2026-10-02 Threatist record created from CVE-2026-91191
- 2026-10-03 Alias added: GHSA-q7r9-65j5-94xj
References
Other 4
- https://ltrxdev.atlassian.net/wiki/spaces/LTRXTS/pages/1889828865/Latest+firmware+for+the+G520+Series+G526+G526RP+G527+G528
- https://www.lantronix.com/technical-support/security-updates/vulnerability-disclosure-policy/vulnerability-library/
- https://www.cisa.gov/news-events/ics-advisories/icsa-26-272-01
- https://github.com/cisagov/CSAF/blob/develop/csaf_files/OT/white/2026/icsa-26-272-01.json
More Lantronix vulnerabilities
- TI-2025-41112 Lantronix EDS5000, G520, and X300 OS Command Injection KEVCVSS 4.0CRITICAL 9.3
- TI-2021-04926 OS command injection in Lantronix CVSS 3.1CRITICAL 9.9
- TI-2021-04937 Stack-based buffer overflow in Lantronix CVSS 3.1CRITICAL 9.9
- TI-2026-55403 Lantronix Autonomous Out-of-Band Devices Unauthenticated Authentication Bypass via snprintf Path Truncation CVSS 4.0CRITICAL 10.0
- TI-2021-04928 OS command injection in Lantronix CVSS 3.1CRITICAL 9.9
- TI-2021-04917 OS command injection in Lantronix CVSS 3.1CRITICAL 9.9
Sources
- CVE-2026-91191 · CVE Program
- CVE-2026-91191 · NVD
- FIRST EPSS
- GHSA-q7r9-65j5-94xj · GitHub Advisory Database · CC BY 4.0
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