CVE-2025-4277: Insyde Software InsydeH2O · Improper Input Validation
Affects Insyde Software InsydeH2OSource CVE Database V5
Not known to be exploited · CVSS 7.5 High.
Data as of 26 Oct 2026, 06:26 UTC
- 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:HExploitation evidence
Disclosed: evidence found.
CVE published 13 Aug 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 2026-10-26.
What to do
AI-suggested
Organizations should prioritize the following mitigations: 1) Inventory and identify all systems running InsydeH2O firmware versions 5.2 to 5.7, focusing on critical infrastructure and high-value assets. 2) Engage with Insyde Software and hardware vendors to obtain and apply firmware updates or patches as soon as they become available. 3) Restrict local administrative access to trusted personnel only and implement strict access controls and monitoring to detect suspicious activities indicative of privilege escalation attempts. 4) Employ hardware-based security features such as Intel Boot Guard or equivalent to protect firmware integrity and prevent unauthorized firmware modifications. 5) Use Endpoint Detection and Response (EDR) solutions capable of detecting anomalous behavior at the kernel and firmware interaction level. 6) Conduct regular security audits and penetration testing focusing on firmware and SMM attack vectors. 7) Implement network segmentation to limit lateral movement opportunities for attackers who gain local access. 8) Educate system administrators about the risks of SMM vulnerabilities and the importance of timely patching and access controls.
Description
Tcg2Smm has a vulnerability which can be used to write arbitrary memory inside SMRAM and execute arbitrary code at SMM level.