Security readout for executives and security teams
Plain-English summary
CVE-2026-20402 is a MediaTek modem flaw that can crash a device’s modem/system when it connects to an attacker-controlled rogue base station. It does not require user interaction or device privileges. The documented impact is denial of service, not data theft or code execution.
Executive priority
Treat as a moderate availability risk. Prioritize confirmation and patch tracking for fleets with affected MediaTek chipsets, especially devices used in sensitive locations where rogue base-station attacks are plausible.
Technical view
MediaTek reports improper input validation in Modem affecting listed chipsets. The issue may cause a system crash and remote denial of service when a UE connects to a rogue base station controlled by an attacker. CVSS 3.1 is 6.5, with adjacent attack vector, low complexity, no privileges, no user interaction, and high availability impact.
Likely exposure
Exposure is limited to devices using the listed MediaTek chipsets and operating in range of a malicious base station. The CVE data marks default status as unaffected outside the listed versions. Mapping chipset exposure to specific phones, tablets, or IoT devices requires OEM inventory confirmation.
Exploitation context
Public sources provided do not indicate active exploitation, and this CVE is not marked KEV. Exploitation requires a rogue base station scenario, making it more constrained than internet-facing attacks but relevant for targeted or proximity-based disruption.
Researcher notes
The source names chipset models, Patch ID MOLY00693083, and Issue ID MSV-5928, but does not provide device-level OEM mappings. CWE is listed as CWE-787, while the description emphasizes improper input validation and crash impact. No exploit details are provided in the cited sources.
Mitigation direction
- Review MediaTek February 2026 security bulletin and Patch ID MOLY00693083.
- Ask device OEMs or carriers for firmware updates containing the MediaTek fix.
- Prioritize updates for managed devices using affected MediaTek chipsets.
- Monitor vendor advisories for device-specific patch availability and rollout timing.
Validation and detection
- Inventory devices and identify MediaTek chipset models in use.
- Compare chipset models against the affected list in the CVE record.
- Confirm OEM firmware includes the MediaTek February 2026 modem fix.
- Track unpatched affected devices as denial-of-service exposure.
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-787: 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-2026-20402 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 Write
Out-of-bounds Write represents a recurring weakness pattern that can create exploitable paths when design, validation, or implementation controls are missing.