Security readout for executives and security teams
Plain-English summary
CVE-2026-20408 is a high-severity MediaTek WLAN chipset vulnerability. A nearby attacker could potentially trigger a heap buffer overflow over wireless proximity and gain elevated privileges. No user interaction or prior privileges are required. The available sources do not show active exploitation.
Executive priority
Prioritize this for environments with MediaTek-based wireless devices, especially routers and embedded products. The risk is high because exploitation needs no user action, but it is limited to adjacent wireless proximity based on current sources. Push vendors for patched firmware and track remediation status.
Technical view
The issue is an out-of-bounds write in WLAN caused by a heap buffer overflow, classified as CWE-122. CVSS 3.1 is 8.8 with adjacent attack vector, low complexity, no privileges, and no user interaction. Affected chipsets listed are MT6890, MT7615, MT7915, MT7916, MT7981, and MT7986. Patch ID is WCNCR00461651; Issue ID is MSV-4758.
Likely exposure
Exposure is most relevant for devices using the listed MediaTek WLAN chipsets, especially Wi-Fi routers, embedded systems, or products with wireless interfaces. The attacker must be proximal or adjacent, not necessarily on the internet. Actual exposure depends on OEM firmware integration and whether the MediaTek patch has been incorporated.
Exploitation context
The CVSS vector indicates exploitation is possible from adjacent network range, requires low complexity, no privileges, and no user interaction. The source bundle marks CISA KEV as false and provides no evidence of public exploitation. Treat this as a serious proximity-based risk, not a confirmed actively exploited issue.
Researcher notes
Public detail is limited to the CVE description, CVSS vector, affected chipsets, and MediaTek bulletin reference. No exploit details, proof of concept, or product-level OEM firmware matrix is provided in the source bundle. Validation should focus on chipset presence, firmware provenance, and vendor confirmation of patch incorporation.
Mitigation direction
- Review MediaTek’s February 2026 product security bulletin for affected chipset guidance.
- Ask OEMs for firmware containing MediaTek patch ID WCNCR00461651.
- Prioritize updates for wireless infrastructure and exposed embedded devices.
- Reduce unnecessary Wi-Fi exposure until patched.
- Monitor vendor advisories for product-specific firmware availability.
Validation and detection
- Inventory devices for listed MediaTek chipsets.
- Map affected chipsets to OEM product models and firmware versions.
- Confirm whether firmware includes patch ID WCNCR00461651.
- Check MediaTek and OEM advisories for updated affected-version details.
- Document devices pending OEM firmware and apply compensating controls.
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-122: 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-2026-20408 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
- High
- CVSS
- 8.8 (3.1)
- Known Exploited
- No
- Published
Vector: CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:H/I:H/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:H/I:H/A:H2.85.9Primary CVE scoreVulnerability scoring details
Base CVSS 3.1 score
8.8HighVector: CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:H/I:H/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.
Heap-based Buffer Overflow
Heap-based Buffer Overflow represents a recurring weakness pattern that can create exploitable paths when design, validation, or implementation controls are missing.