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Findings

CVE-2026-12855

VU#553437: InsydeH2O IHISI SMM is vulnerable to unsafe memory write operations

Published Oct 1, 2026 · CERT/CC

Overview An Out-of-bounds Write vulnerability in the InsydeH2O IHISI software used by HP PC BIOS can allow a local attacker with OS kernel privileges to perform arbitrary physical memory writes, including writes to System Management RAM (SMRAM). Because the vulnerable code executes in System Management Mode (SMM), successful exploitation can allow an attacker to modify SMM-protected memory and potentially achieve arbitrary code execution in SMM. Depending on the platform's memory and firmware configuration, the arbitrary physical memory write primitive may also have i

Code

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Timeline

Detection, updates, and resolution for this record.

  1. Oct 1, 2026 · CERT/CC Vulnerability Notes

    Detected

    Overview An Out-of-bounds Write vulnerability in the InsydeH2O IHISI software used by HP PC BIOS can allow a local attacker with OS kernel privileges to perform arbitrary physical memory writes, including writes to System Management RAM (SMRAM). Because the vulnerable code executes in System Management Mode (SMM), successful exploitation can allow an attacker to modify SMM-protected memory and pot

Sources

  • CERT/CC Vulnerability NotesGovernment advisoryCVE-2026-12855

    Overview An Out-of-bounds Write vulnerability in the InsydeH2O IHISI software used by HP PC BIOS can allow a local attacker with OS kernel privileges to perform arbitrary physical memory writes, including writes to System Management RAM (SMRAM). Because the vulnerable code execut

    kb.cert.org
  • CVE.orgVulnerability recordCVE-2026-12855

    Official CVE identifier

    cve.org