CVE-2026-20466

Physical privilege escalation via secure-boot heap overflow

Published Aug 3, 2026 · Updated Aug 3, 2026

Heap overflow in MediaTek Chipset secure boot allows physically proximate attackers to escalate privileges on MT2737, MT6880, MT6890, and MT6990. MediaTek identifies the locus as sec boot but has not published which operation exceeds the heap buffer or which input reaches it. Physical access is required, but no prior execution privileges or user interaction are needed; successful exploitation compromises protected data and system integrity.

CVSS severity6.1
Medium
EPSS probability0.17%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Heap overflow in MediaTek Chipset secure boot allows physically proximate attackers to escalate privileges on MT2737, MT6880, MT6890, and MT6990. MediaTek identifies the locus as sec boot but has not published which operation exceeds the heap buffer or which input reaches it. Physical access is required, but no prior execution privileges or user interaction are needed; successful exploitation compromises protected data and system integrity.

The record

CVE
CVE-2026-20466
Published
Aug 3, 2026
Updated
Aug 3, 2026
Vendor
MediaTek
Product
MediaTek Chipset
Classifications
CWE-787
Attack vector
physical
Privileges
unauthenticated

Timeline

How it unfolded

  1. Aug 3, 2026CVE publishedPublication date reported by the CVE source.
  2. Aug 3, 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?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=MT2737
  2. Affected versionversion=MT6880
  3. Affected versionversion=MT6890
  4. Affected versionversion=MT6990

What conditions does exploitation require?

Attack vectorphysical
Required privilegesunauthenticated

What is affected?

MediaTek · MediaTek Chipsetversion=MT2737; version=MT6880; version=MT6890; version=MT6990

Published CVSS scores

6.1CISA-ADPCVSS:3.1/AV:P/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N

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.

Daily unique IPsNo honeypot observations are available for this CVE in the selected window.

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 exploitUnconfirmed

Weakness, pattern, technique

CWE-787Out-of-bounds Write

Public exploit references

No public exploit references are available in this record.

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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