Firmware failure via PlatformLangCodes buffer overflow
Published Sep 3, 2026 · Updated Sep 3, 2026
Buffer overflow in VariableEditSmm in InsydeH2O before 01.01.04.0008 allows physically proximate attackers to cause firmware failure. The driver mishandles PlatformLangCodes UEFI variable data and overflows a buffer, but Insyde has not disclosed the exact faulty operation. Exploitation requires physical access, high privileges, and user interaction; the documented consequence is resource exhaustion and firmware failure.
Summary
What happened
Buffer overflow in VariableEditSmm in InsydeH2O before 01.01.04.0008 allows physically proximate attackers to cause firmware failure. The driver mishandles PlatformLangCodes UEFI variable data and overflows a buffer, but Insyde has not disclosed the exact faulty operation. Exploitation requires physical access, high privileges, and user interaction; the documented consequence is resource exhaustion and firmware failure.
The record
- CVE
- CVE-2021-43614
- Published
- Sep 3, 2026
- Updated
- Sep 3, 2026
- Vendor
- Insyde Software
- Product
- InsydeH2O UEFI BIOS
- Classifications
- Unavailable
- Attack vector
- physical
- Privileges
- admin
Timeline
How it unfolded
- Sep 3, 2026CVE publishedPublication date reported by the CVE source.
- Sep 3, 2026Record updatedLatest update available in the CVE record.
Exploitability
Present is not the same as exploitable
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Is a vulnerable build present?
Compare these published version ranges with your installed build and any vendor patches.
- Affected versionversion=InsydeH2OUvePkg <01.01.04.0008
What conditions does exploitation require?
What is affected?
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.
Weakness, pattern, technique
No sourced classifications are available.
Public exploit references
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Technologies
Your stack
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Your stack
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