Raw vector
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:HSummary
CVE-2026-20423 is a high-severity Exposed Dangerous Method or Function (CWE-749) vulnerability in Mediatek Nbiot Sdk. 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 2th 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 AC-3 (Access Enforcement) and AC-6 (Least Privilege) — see the control section below for these in your framework.
Deeper analysis AI-assisted summary
Synthesised by an AI model from the NVD description and linked references — a reading aid, not an authoritative source.
CVE-2026-20423 is a vulnerability in the wlan STA driver that enables an out-of-bounds write due to a missing bounds check. This issue, tracked as Issue ID MSV-4956 and addressed by Patch ID WCNCR00465314, affects MediaTek components and carries a CVSS v3.1 base score of 7.8 (AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H). It is associated with CWE-749 and CWE-787.
A local attacker with user execution privileges can exploit this vulnerability without requiring user interaction. Successful exploitation leads to escalation of privilege, potentially granting high-impact access to confidentiality, integrity, and availability of the affected system.
MediaTek's March 2026 Product Security Bulletin at https://corp.mediatek.com/product-security-bulletin/March-2026 provides details on mitigation, including the referenced patch WCNCR00465314. Security practitioners should apply vendor patches promptly to affected devices.
OWASP Top 10 for Web (2025)
EU & UK References
- 🇪🇺 ENISA EUVD: EUVD-2026-9151
Vulnerability Data
In wlan STA driver, there is a possible out of bounds write due to a missing bounds check. This could lead to local escalation of privilege with User execution privileges needed. User interaction is not needed for exploitation. Patch ID:…
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WCNCR00465314; Issue ID: MSV-4956.
- CWE(s)
Related Threats
MITRE ATT&CK Enterprise Techniques
CVEs Like This One
Affected Assets
Mitigating Controls
Control response
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- 4 hardening rules · 2 OS baselines
V8.2.1
Mitigating Controls (NIST 800-53 r5) AI
Access enforcement directly stops unauthorized callers from invoking dangerous API methods or functions.
Least privilege restricts which users or processes may reach dangerous methods, limiting exposure.
Least functionality removes or disables non-essential dangerous methods from the exposed interface altogether.
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.
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.
Enforcing least-privilege authorization directly prevents unrestricted dangerous API methods.
Secure SDLC practices stop developers from exposing dangerous functions in the first place.
Vulnerability identification processes will surface exposed dangerous methods during assessment.
Logical access controls at the network/environment layer can limit reachability of exposed functions.
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.
Security testing can detect exposed dangerous functions, but does not prevent their initial introduction.
Restricting privileged utility programs reduces exposure of dangerous functions, but does not eliminate the underlying weakness.
Privileged access rights limit who can invoke dangerous methods, but do not address whether the method itself should exist.
Secure development life cycle requires removal or protection of dangerous APIs during design and coding.
Application security requirements can mandate that dangerous methods are not exposed in interfaces.
Secure architecture principles discourage exposing dangerous functions, but do not guarantee their absence.
Hardening callouts derived
Configuration rules from DISA STIG baselines that bear on weaknesses of the type cited by this CVE. Each rule is shown with the relationship its mapping actually records, against the CWE it was authored against. Derived via CVE→CWE over `controls_xwalks` (authoritative rows only; rows rated `none` are excluded).
Ubuntu 22.04 (3 rules)
- V-260559 Ubuntu 22.04 LTS must ensure only users who need access to security functions are part of sudo group. prevents CWE-749
- V-260529 Ubuntu 22.04 LTS must be configured so that remote X connections are disabled, unless to fulfill documented and validated mission requirements. prevents CWE-749
- V-260557 Ubuntu 22.04 LTS must be configured to use AppArmor. prevents CWE-749
Ubuntu 24.04 (1 rule)
- V-270748 Ubuntu 24.04 LTS must ensure only users who need access to security functions are part of sudo group. prevents CWE-749