CVE-2026-36738Public exploit

Physical device compromise via unauthenticated UART

Published May 13, 2026 · Updated May 13, 2026

Incorrect access control in U-SPEED T18-21K firmware 1.0 allows physically proximate attackers to gain unrestricted device access. The production PCB exposes a UART debug interface that accepts serial-console connections without authentication, authorization, or access restrictions. Exploitation requires opening the router enclosure and attaching UART hardware; console access exposes configuration data and command execution.

CVSS severity6.8
Medium
EPSS probability0.30%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Incorrect access control in U-SPEED T18-21K firmware 1.0 allows physically proximate attackers to gain unrestricted device access. The production PCB exposes a UART debug interface that accepts serial-console connections without authentication, authorization, or access restrictions. Exploitation requires opening the router enclosure and attaching UART hardware; console access exposes configuration data and command execution.

The record

CVE
CVE-2026-36738
Published
May 13, 2026
Updated
May 13, 2026
Vendor
Unknown vendor
Product
Unknown product
Classifications
CWE-284, T1200
Attack vector
physical
Privileges
unauthenticated

Timeline

How it unfolded

  1. May 13, 2026CVE publishedPublication date reported by the CVE source.
  2. May 13, 2026Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Affected buildAffected product and version details are unavailable.

What conditions does exploitation require?

Attack vectorphysical
Required privilegesunauthenticated

What is affected?

Affected products and versions are unavailable in this record.

Published CVSS scores

6.8CISA-ADPCVSS:3.1/AV:P/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

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No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectorphysical
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitPublished

Weakness, pattern, technique

CWE-284Improper Access Control
T1200Hardware Additions

Public exploit references

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

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Your stack

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