An improper verification of cryptographic signature vulnerability exists in protocol gateways because the device does not properly verify t…

published 2026-10-02 last mo. modified 2026-10-02 last mo. also EUVD-2026-91373

cvss: 8.6; version 4.0, CNA
cisa kev: Not listed; not in CISA's catalog
epss: 0.2%; EPSS 0.2% chance of exploitation in 30 days, percentile 8%
public exploits: 0; none known

An improper verification of cryptographic signature vulnerability exists in protocol gateways because the device does not properly verify the cryptographic authenticity of firmware images before installation. An attacker with high privileges and access to the firmware update interface could provide a specially crafted or modified firmware image, causing it to be installed on the device. Successful exploitation could allow the attacker to execute unauthorized code, compromise the integrity and availability of the device, and persist malicious modifications across subsequent firmware updates.

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CISA SSVC

Exploitation: none
Automatable: no
Technical impact: total
Assessed: last mo. (2026-10-02)

Exploit prediction

0.19% chance of exploitation in the next 30 days, higher than 8% of all scored CVEs (FIRST EPSS, 2026-11-11).

CVSS scores

assigned by	version	score	vector
CNA	4.0	8.6	CVSS:4.0/AV:N/AC:L/AT:N/PR:H/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N
CNA	4.0	8.6	CVSS:4.0/AV:N/AC:L/AT:N/PR:H/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X

Affected products

Moxa MGate MB3170 Series
Moxa MGate MB3270 Series

Classification

Weakness

CWE-347 Improper Verification of Cryptographic Signature

References

moxa.com /en/support/product-support/security-advisory/mpsa-269540-cve-2026-86325,-cve-2026-86326-two-vulnerabilities-i
vendor-advisory

Sources

CVE List CVE-2026-86326
NVD CVE-2026-86326

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