Raw vector
CVSS:3.1/AV:A/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:HSummary
CVE-2026-20459 is a medium-severity Authentication Bypass Using an Alternate Path or Channel (CWE-288) vulnerability in Mediatek (inferred from references). Its CVSS base score is 5.3 (Medium).
Operationally, exploitation aligns with the MITRE ATT&CK technique Application or System Exploitation (T1499.004); ranked at the 7th 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) and SC-5 (Denial-of-service Protection) — see the control section below for these in your framework.
OWASP Top 10 for Web (2025)
EU & UK References
- 🇪🇺 ENISA EUVD: EUVD-2026-40872
Vulnerability Data
In Modem, there is a possible system crash due to improper input validation. This could lead to remote denial of service, if a UE has connected to a rogue base station controlled by the attacker, with no additional execution privileges…
more
needed. User interaction is not needed for exploitation. Patch ID: MOLY01816800; Issue ID: MSV-6842.
- CWE(s)
Related Threats
MITRE ATT&CK Enterprise TechniquesAI
Why these techniques?
Improper input validation in modem enables remote system crash/DoS via rogue base station, directly matching application/system exploitation for availability impact.
CVEs Like This One
Affected Assets
Mitigating Controls
Control response
Mitigating Controls (NIST 800-53 r5) AI
Directly enforces validation of all inputs received over the air interface, eliminating the root cause of the modem crash from malformed data sent by a rogue base station.
Boundary protection mechanisms can restrict or validate connections to untrusted base stations before they are allowed to send traffic to the modem.
Provides denial-of-service protections that can limit the impact of crafted inputs intended to crash the modem stack.
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.
Requiring authentication on every channel and path directly eliminates alternate-path bypasses.
Enforcing authorizations and least privilege across all access vectors prevents unauthenticated alternate paths.
Protecting networks and environments from unauthorized logical access blocks bypass via undocumented channels.
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 alternate-path bypasses but does not prevent them in production.
Secure authentication control directly mitigates bypass by requiring strong, consistent authentication on all paths.
Access control policy directly addresses alternate authentication paths by requiring all channels to enforce authentication.
Authentication information management ensures credentials and mechanisms are consistently applied across all access paths.
Access rights provisioning and review prevent bypass via unmonitored or alternate channels.
Privileged access rights control reduces risk of bypass through elevated or alternate paths.