Local privilege escalation via unchecked PCIe write
Published Feb 2, 2026 · Updated Feb 2, 2026
Out-of-bounds write in MediaTek chipset MT6991, MT6993, and MT8678 allows local users to elevate privileges through PCIe processing. The PCIe component performs a memory write without checking the destination boundary, allowing data to be written outside the intended buffer. Exploitation requires existing System privilege and no user interaction; MediaTek has not disclosed the triggering input or resulting privilege level.
Summary
What happened
Out-of-bounds write in MediaTek chipset MT6991, MT6993, and MT8678 allows local users to elevate privileges through PCIe processing. The PCIe component performs a memory write without checking the destination boundary, allowing data to be written outside the intended buffer. Exploitation requires existing System privilege and no user interaction; MediaTek has not disclosed the triggering input or resulting privilege level.
The record
- CVE
- CVE-2026-20417
- Published
- Feb 2, 2026
- Updated
- Feb 2, 2026
- Vendor
- Unknown vendor
- Product
- Unknown product
- Classifications
- CWE-787, T1068
- Attack vector
- local
- Privileges
- admin
Timeline
How it unfolded
- Feb 2, 2026CVE publishedPublication date reported by the CVE source.
- Feb 2, 2026Record updatedLatest update available in the CVE record.
Exploitability
Present is not the same as exploitable
Compare your product and version with the public record. A matching version still requires validation against your environment.
Is a vulnerable build present?
What conditions does exploitation require?
What is affected?
Affected products and versions are unavailable in this record.
Published CVSS scores
CVSS describes severity. EPSS estimates exploitation probability.
Attacks
What attackers are doing with it
Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.
Public exploit references
No public exploit references are available in this record.
Labels summarize the accepted research assessment. They do not indicate a test against your environment.
Technologies
Your stack
See the directory against your own environment.
Your stack
Check the software in your environment
Book a demo to see how Hinoki identifies affected software and validates exploitability in your environment.
Book a demo