Cyber Resilience

CVE-2026-20455

Memory Safety in Mediatek Mt6739 Firmware

Published
01 June 2026
Modified
22 July 2026
Patch / advisory
CVSS Score v3.1 7.8
Click a component to see what it means
Raw vectorCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
EPSS Score 0.0011 1th percentile
Risk Priority 54 floored blend · peak EPSS

Summary

CVE-2026-20455 is a high-severity Out-of-bounds Write (CWE-787) vulnerability in Mediatek Mt6739 Firmware. Its CVSS base score is 7.8 (High).

Operationally, exploitation aligns with the MITRE ATT&CK technique Exploitation for Privilege Escalation (T1068); ranked at the 1th 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 SA-11 (Developer Testing and Evaluation) and SA-15 (Development Process, Standards, and Tools) — see the control section below for these in your framework.

EU & UK References

Vulnerability Data

In geniezone, there is a possible out of bounds write due to a missing bounds check. This could lead to local escalation of privilege if a malicious actor has already obtained the System privilege. User interaction is not needed for…

more

exploitation. Patch ID: ALPS10873936; Issue ID: MSV-6784.

CWE(s)

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.
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.
T1203 Exploitation for Client Execution Execution
Adversaries may exploit software vulnerabilities in client applications to execute code.
T1210 Exploitation of Remote Services Lateral Movement
Adversaries may exploit remote services to gain unauthorized access to internal systems once inside of a network.
T1211 Exploitation for Stealth Stealth
Adversaries may exploit vulnerabilities to evade detection by hiding activity, suppressing logging, or operating within trusted or unmonitored components.
T1212 Exploitation for Credential Access Credential Access
Adversaries may exploit software vulnerabilities in an attempt to collect credentials.
Derived from this CVE’s CWE(s) via the direct CWE→ATT&CK cross-walk.

CVEs Like This One

CVE-2023-32840Same product: Mediatek Mt6739
CVE-2024-20039Same product: Mediatek Mt6739
CVE-2023-20819Same product: Mediatek Mt6739
CVE-2023-32886Same product: Mediatek Mt6835
CVE-2023-32874Same product: Mediatek Mt6781
CVE-2024-20131Same product: Mediatek Mt6789
CVE-2023-32888Same product: Mediatek Mt6835
CVE-2024-20151Same product: Mediatek Mt6789
CVE-2025-20634Same product: Mediatek Mt6835
CVE-2024-20068Same product: Mediatek Mt6835

Affected Assets

mediatek
mt6739 firmware
all versions
mediatek
mt6761 firmware
all versions
mediatek
mt6765 firmware
all versions
mediatek
mt6768 firmware
all versions
mediatek
mt6781 firmware
all versions
mediatek
mt6789 firmware
all versions
mediatek
mt6835 firmware
all versions
mediatek
mt6853 firmware
all versions
mediatek
mt6855 firmware
all versions
mediatek
mt6877 firmware
all versions
+26 more product configuration(s) — see NVD for full list

Mitigating Controls

Mitigating Controls (NIST 800-53 r5) AI

Developer testing and evaluation (including fuzzing and bounds checks) finds out-of-bounds write flaws before deployment.

Requiring documented secure-development standards and tools can mandate bounds-checked coding practices that avoid the weakness.

Input validation can structurally reject or sanitize data that would otherwise trigger an out-of-bounds write.

Memory-protection mechanisms limit the exploitability and blast radius of a successful out-of-bounds write.

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.

PR.PS-06 mostly match
prevents

Secure-development practices (static analysis, bounds checking, code review) are the primary means of preventing out-of-bounds writes.

ID.RA-01 partial match
prevents

Vulnerability scanning and recording can discover out-of-bounds write flaws so they can be remediated.

PR.PS-02 partial match
prevents

Patching or replacing vulnerable software directly eliminates known instances of this coding weakness.

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.

finds

Security testing in development and acceptance can detect and prevent out-of-bounds write defects.

prevents

Secure development life cycle mandates practices that prevent out-of-bounds writes.

prevents

Application security requirements can specify bounds-checking and safe memory handling.

prevents

Secure architecture and engineering principles reduce the likelihood of buffer overflows.

prevents

Secure coding directly addresses out-of-bounds writes through language choice and coding standards.

prevents

Change management can enforce review gates that catch unsafe memory operations before deployment.

References