CVE-2025-4275: Insyde Software InsydeH2O · Improper Access Control
Affects Insyde Software InsydeH2OSource CVE Database V5
Not known to be exploited · CVSS 7.8 High.
Data as of 26 Oct 2026, 17:16 UTC
- EPSS
- 0.4% chance of exploitation in 30 days – higher than 41% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.
CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:C/C:H/I:H/A:HExploitation evidence
Disclosed: evidence found.
CVE published 11 Jun 2025
Detectable: no evidence on record.
No public nuclei template indexed
Weaponised: no evidence on record.
No public exploit code indexed in Metasploit or Exploit-DB
Exploited in the wildExploited: no evidence on record.
Not in CISA KEV and no source reports exploitation
Observed by OffSeq MirageSeen by 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 26 Oct 2026.
What to do
AI-suggested
- Immediate inventory and identification of all systems running InsydeH2O firmware versions 5.2 through 5.7 is essential.
- Monitor Insyde Software and hardware vendors for official security patches or firmware updates addressing CVE-2025-4275 and apply them promptly upon release.
- Implement strict physical security controls to limit unauthorized local access to systems, as exploitation requires local access.
- Employ endpoint detection and response (EDR) tools capable of monitoring firmware-level anomalies and suspicious boot-time activities.
- Use hardware-based security features such as TPM (Trusted Platform Module) and enable measured boot where possible to detect unauthorized firmware modifications.
- Restrict and monitor administrative privileges to reduce the risk of privilege escalation that could facilitate exploitation.
- Conduct regular firmware integrity checks and audits to detect unauthorized changes to NVRAM variables or boot configurations.
- Educate IT and security teams about the risks of firmware-level attacks and ensure incident response plans include firmware compromise scenarios.
- Consider network segmentation to isolate critical systems and limit lateral movement if a device is compromised.
- Maintain up-to-date backups and recovery procedures to restore systems in case of compromise.
Description
A vulnerability in the digital signature verification process does not properly validate variable attributes which allows an attacker to bypass signature verification by creating a non-authenticated NVRAM variable. An attacker may to execute arbitrary signed UEFI code and bypass Secure Boot.