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CVE-2025-4276VulnerabilityPublished Updated

CVE-2025-4276: Insyde Software InsydeH2O · Improper Input Validation

Affects Insyde Software InsydeH2OSource CVE Database V5

0

Not known to be exploited · CVSS 7.5 High.

Data as of 25 Oct 2026, 19:02 UTC

CVSS 3.1 base score
7.5High
How severe the flaw is on the 0–10 CVSS scale.
EPSS
0.1% chance of exploitation in 30 days – higher than 3% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.
CVSS:3.1/AV:L/AC:H/PR:H/UI:N/S:C/C:H/I:H/A:H

Exploitation evidence

  1. Disclosed: evidence found.

    CVE published 13 Aug 2025

  2. Detectable: no evidence on record.

    No public nuclei template indexed

  3. Weaponised: no evidence on record.

    No public exploit code indexed in Metasploit or Exploit-DB

  4. Exploited in the wild: no evidence on record.

    Not in CISA KEV and no source reports exploitation

  5. Observed by OffSeq Mirage: no evidence on record.

    No attack traffic recorded by OffSeq Mirage sensors

A missing step is not evidence of safety. Sources: cve.org (opens in a new tab), the Metasploit, Exploit-DB and nuclei-templates index as of 2026-10-25.

What to do

AI-suggested

Given the absence of official patches, European organizations should implement a multi-layered mitigation strategy: 1) Conduct an immediate inventory to identify systems running InsydeH2O firmware versions 5.3 to 5.7. 2) Restrict physical and administrative access to affected systems to minimize the risk of local privilege escalation. 3) Employ hardware-based security features such as Intel Boot Guard or AMD equivalent to enforce firmware integrity and prevent unauthorized firmware modifications. 4) Enable and enforce BIOS/UEFI password protections and secure boot mechanisms to reduce unauthorized firmware access. 5) Monitor system logs and firmware integrity using specialized tools capable of detecting anomalous SMM activity or firmware tampering. 6) Engage with OEMs and Insyde Software for timely updates or firmware patches and plan for rapid deployment once available. 7) Incorporate firmware scanning into vulnerability management programs and penetration testing to proactively identify exploitation attempts. 8) Educate IT and security teams about the risks of firmware vulnerabilities and the importance of layered defenses beyond the OS level.

Description

UsbCoreDxe has a vulnerability which can be used to write arbitrary memory inside SMRAM and execute arbitrary code at SMM level.

References

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