Security readout for executives and security teams
Plain-English summary
CVE-2026-20420 affects listed MediaTek chipsets. A nearby attacker operating a rogue base station could crash the modem after a device connects, causing denial of service. It does not claim data theft or code execution. Business impact is service disruption for affected mobile or connected devices in hostile radio environments.
Executive priority
Treat as a moderate availability risk. Prioritize if your organization relies on affected MediaTek-based devices for field operations, critical communications, IoT, or travel in higher-risk locations. The main concern is disruption, not confirmed compromise.
Technical view
MediaTek describes incorrect error handling in Modem, associated with CWE-125, leading to possible system crash. CVSS 3.1 is 6.5: AV:A/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H. Exploitation requires the UE to connect to an attacker-controlled rogue base station. Patch ID is MOLY01738313; Issue ID MSV-5935.
Likely exposure
Exposure is limited to devices using the listed MediaTek chipsets and modem firmware that has not received the vendor fix. The attack is not internet-routable; it requires proximity or radio adjacency and a rogue base station scenario.
Exploitation context
The source bundle does not indicate active exploitation, and KEV is false. The described attacker needs no privileges or user interaction, but must control a rogue base station that the target UE connects to.
Researcher notes
Evidence is limited to the CVE record and MediaTek bulletin reference. The affected list is chipset-level, so product-level exposure depends on OEM implementation and firmware distribution. No public exploit status or detailed technical advisory is provided in the supplied sources.
Mitigation direction
- Identify products using the listed MediaTek chipsets.
- Check MediaTek and device OEM advisories for updates containing patch ID MOLY01738313.
- Deploy validated modem/baseband firmware updates through normal OEM or carrier channels.
- Prioritize exposed fleets operating in untrusted or high-risk radio environments.
Validation and detection
- Inventory affected chipset models across managed mobile, IoT, and embedded assets.
- Compare installed firmware against OEM release notes referencing CVE-2026-20420 or MOLY01738313.
- Confirm vendor bulletin applicability for each device model and region.
- Track remediation status for devices lacking OEM firmware availability.
Public sources used
Generated from the cited source records. This long-tail analysis has not been individually reviewed by a named human.
Conservative CVE-to-ATT&CK context
These mappings and lookup hints may be relevant to the vulnerability behavior, CWE, affected product, or exposure path. Glexia-inferred context is not an official MITRE, ATT&CK, CWE, or CVE Program mapping.
ATT&CK lookup starting points
Use these exact CWE pages and searches to review the Glexia ATT&CK library from this CVE's weakness and description context.
CWE-125: Exact CWE lookup
Use the exact CWE identifier as the starting point before reviewing related ATT&CK behavior. Open the exact CWE lookup page first, then review the ATT&CK searches from that MITRE weakness context. This is a Glexia lookup hint, not an official ATT&CK mapping.
Open ATT&CK lookupCVE-2026-20420 mapping review
Open the CVE-to-ATT&CK bridge for reviewed, inferred, or future official mappings tied to this CVE.
Open ATT&CK lookup- Severity
- Medium
- CVSS
- 6.5 (3.1)
- Known Exploited
- No
- Published
Vector: CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
CNA and ADP enrichment extracted from CVE v5
These fields come from the CVE record and ADP containers, not from Glexia's Take. They preserve time-varying source decisions such as CISA SSVC, KEV status, CVSS metrics, and provider references.
CVSS vector scores
1 official scoreWe collect every scored CVSS vector available in the official CNA and ADP containers. When more than one version is present, the table keeps the source vectors side by side instead of collapsing them into the highest score.
CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H2.83.6Primary CVE scoreVulnerability scoring details
Base CVSS 3.1 score
6.5MediumVector: CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
Source materials
- CVE List V5 sourceCVE List V5
- https://corp.mediatek.com/product-security-bulletin/February-2026CVE reference
Products and packages named in the record
CWE details
CWE links open Glexia weakness intelligence pages with official CWE context, developer remediation guidance, and related CVE mappings.
Out-of-bounds Read
Out-of-bounds Read represents a recurring weakness pattern that can create exploitable paths when design, validation, or implementation controls are missing.