Security readout for executives and security teams
Plain-English summary
CVE-2026-20401 is a MediaTek modem flaw that can crash an affected device when it connects to an attacker-controlled rogue base station. The business impact is denial of service, not data theft or code execution based on available sources. Risk is most relevant to mobile or cellular-connected assets using listed MediaTek chipsets.
Executive priority
Treat as a targeted availability risk for fleets using affected MediaTek-based cellular devices. It does not indicate data compromise, but outages could matter in field operations, logistics, healthcare, or safety workflows. Prioritize vendor confirmation and patch rollout over emergency response.
Technical view
MediaTek describes an uncaught exception in Modem that may cause a system crash. Exploitation requires a UE to connect to a rogue base station controlled by the attacker. CVSS 3.1 is 6.5, AV:A/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H. CWE-617 is assigned. Patch ID is MOLY01738310; Issue ID is MSV-5933.
Likely exposure
Exposure depends on whether organizational phones, tablets, IoT, or cellular equipment contain the listed MediaTek chipsets and receive MediaTek/OEM modem firmware updates. The source marks default status as unaffected except for the named chipset versions.
Exploitation context
No public source in the bundle reports active exploitation, and CISA KEV is false. The attacker needs rogue base station capability and radio proximity sufficient for a UE to connect. No user interaction or device privileges are required after that condition is met.
Researcher notes
The source description is brief and does not name specific phone models, firmware builds, or a public proof of concept. Analysis should focus on chipset-to-device mapping, OEM patch propagation, and whether modem firmware includes MOLY01738310. Avoid assuming impact beyond system crash and denial of service.
Mitigation direction
- Check MediaTek February 2026 bulletin and OEM advisories for firmware containing patch ID MOLY01738310.
- Prioritize updates for devices with listed MediaTek chipsets used in sensitive or availability-critical roles.
- Ask device vendors or carriers whether their firmware includes the MediaTek modem fix.
- Reduce reliance on unpatched cellular devices where outage impact is unacceptable.
Validation and detection
- Inventory cellular devices and map models to MediaTek chipset identifiers listed in the advisory.
- Confirm firmware or security patch level with the OEM, carrier, or device management platform.
- Verify whether patch ID MOLY01738310 is included in available modem firmware updates.
- Track exceptions for unsupported devices that cannot receive the vendor fix.
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-617: Exact CWE lookup
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Open ATT&CK lookupCVE-2026-20401 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.
Reachable Assertion
Reachable Assertion represents a recurring weakness pattern that can create exploitable paths when design, validation, or implementation controls are missing.