Cyber Resilience

CVE-2026-20524

Mediatek Mt6899 Firmware

Published
05 October 2026
Modified
08 October 2026
Patch / advisory
View advisory
CVSS Score v3.1 8.4
Click a component to see what it means
Raw vectorCVSS:3.1/AV:L/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
EPSS Score 0.0013 3th percentile
Risk Priority 59 floored blend · peak EPSS

CVSS and EPSS are reproduced from their sources (NVD, FIRST EPSS). Risk Priority is our own derived reading, not an NVD score.

Summary

CVE-2026-20524 is a high-severity Improper Validation of Specified Index, Position, or Offset in Input (CWE-1285) vulnerability in Mediatek Mt6899 Firmware. Its CVSS base score is 8.4 (High).

Operationally, exploitation aligns with the MITRE ATT&CK technique Exploitation for Privilege Escalation (T1068); ranked at the 3th percentile by exploit likelihood (below the median); it is not currently listed in the CISA KEV catalog.

The strongest mitigations our analysis identified map to SI-10 (Information Input Validation) — see the control section below for these in your framework.

EU & UK References

Vulnerability Data

In apu, there is a possible memory corruption due to improper input validation. This could lead to local escalation of privilege with no additional execution privileges needed. User interaction is not needed for exploitation. Patch ID: ALPS11249004; Issue ID: MSV-9170.

CWE(s)
CWE-1285

Related Threats

MITRE ATT&CK Enterprise Techniques

T1068 Exploitation for Privilege Escalation Privilege Escalation
Adversaries may exploit software vulnerabilities in an attempt to elevate privileges.
attack.mitre.org →
T1190 Exploit Public-Facing Application Initial Access
Adversaries may attempt to exploit a weakness in an Internet-facing host or system to initially access a network.
attack.mitre.org →
T1203 Exploitation for Client Execution Execution
Adversaries may exploit software vulnerabilities in client applications to execute code.
attack.mitre.org →
T1210 Exploitation of Remote Services Lateral Movement
Adversaries may exploit remote services to gain unauthorized access to internal systems once inside of a network.
attack.mitre.org →
T1212 Exploitation for Credential Access Credential Access
Adversaries may exploit software vulnerabilities in an attempt to collect credentials.
attack.mitre.org →
Derived from this CVE’s CWE(s) via the direct CWE→ATT&CK cross-walk.

CVEs Like This One

CVE-2026-20523Same product: Mediatek Mt6993
CVE-2026-20522Same product: Mediatek Mt6993
CVE-2026-20447Same product: Mediatek Mt6899
CVE-2025-20796Same vendor: Mediatek
CVE-2026-20451Same product: Mediatek Mt6899
CVE-2026-20449Same product: Mediatek Mt6899
CVE-2026-20521Same product: Mediatek Mt6899
CVE-2025-20756Same product: Mediatek Mt8793
CVE-2026-20586Same product: Mediatek Mt8668
CVE-2026-20436Same vendor: Mediatek

Affected Assets

mediatek
mt6899 firmware
all versions
mediatek
mt6993 firmware
all versions
mediatek
mt8668 firmware
all versions
mediatek
mt8781 firmware
all versions
mediatek
mt8793 firmware
all versions
mediatek
mt8910 firmware
all versions

Mitigating Controls

Control response

Prevent
Stop it (NIST 800-53)

—

Detect
Catch it (NIST detect / respond)

—

Harden
Shrink the surface (DISA STIG)

—

Validate
Prove the fix (OWASP ASVS)
  • V2.1.1
  • V2.2.1
  • V2.2.2
  • V5.3.3

Mitigating Controls (NIST 800-53 r5) AI

SI-10 Information Input Validation partial match

Requires explicit validation of supplied indices/offsets/positions before they are used to access buffers or other indexable resources.

Mitigating Controls (NIST CSF 2.0) AI

Derived directly from the weakness types (CWEs) cited in the NVD entry via our AI-authored CWE→CSF cross-walk (authority under review) — links open the control.

ID.RA-01 partial match
blocks

Vulnerability identification processes can discover missing index validation via scanning or reviews.

PR.PS-02 partial match
blocks

Patching and replacement can remediate instances of the weakness after discovery.

PR.PS-06 partial match
blocks

Secure SDLC practices directly require input validation, preventing this class of flaw at development time.

Mitigating Controls (ISO/IEC 27001:2022 Annex A) AI

Derived directly from the weakness types (CWEs) cited in the NVD entry via our AI-authored CWE→ISO cross-walk (authority under review) — links open the control.

A.8.25 Secure development life cycle partial match
blocks

A.8.25 mandates secure SDLC practices including secure coding guidelines, security requirements, checkpoints, testing (scans/penetration), and developer training that reach index/offset validation defects, but leaves a bounded remainder (e.g. incomplete enforcement across all languages, outsourced code without full assurance, or post-release changes)

A.8.26 Application security requirements partial match
blocks

A.8.26 explicitly lists resilience against SQL injections plus input validation/integrity checks (items d, j) as application security requirements to identify/address via risk assessment; this reaches a minority slice of index/offset validation defects but leaves most instances (non-web, non-SQL, incomplete enforcement, second-order) unaddressed by the requirements-setting process itself.

A.8.27 Secure system architecture and engineering principles partial match
blocks

A.8.27 mandates security engineering principles including data validation/sanitization, distrust-external-input, security-by-design reviews against attack patterns, and hardening; this reaches a minority slice of CWE-1285 (index/offset validation in new designs) but leaves most instances (existing code, incomplete application of principles, or post-design defects) exploitable.

A.8.28 Secure coding partial match
prevents

Secure coding standards directly require validation of indices, positions, and offsets before use.

A.8.29 Security testing in development and acceptance partial match
finds

Security testing can detect missing or incorrect index validation during development and acceptance.

A.8.9 Configuration management partial match
removes

References