CVE-2025-4277
Official description Straight from the sourceThe vendor's or NVD's own wording, published unedited. Authoritative, but often terse — it says what broke, rarely what to do.
NVD · uneditedTcg2Smm has a vulnerability which can be used to write arbitrary memory inside SMRAM and execute arbitrary code at SMM level.
Technical summary Written by usOur analysis, written from the advisory, the CVSS vector and the affected-version data. It adds context the advisory leaves out, and never invents facts that are not in the source.
dbcve analysis · moderate confidenceTcg2Smm, a UEFI firmware component implementing TCG (Trusted Computing Group) functionality, contains a vulnerability allowing an attacker to write arbitrary memory within SMRAM (System Management RAM) and execute code at SMM (System Management Mode) privilege level. This represents a critical firmware-level memory corruption issue that bypasses OS security controls since SMM operates with higher privileges than the operating system.
Verify against the referenced sources before acting — the references below are authoritative for this CVE, this summary is not.
CVSS breakdown How the score is builtThe industry scoring standard. It rates how the flaw is reached, what it takes to exploit, and what an attacker gains — the score is derived from those, not the other way round.
From the vector- Attack vector
- Local
- Complexity
- High
- Privileges
- High
- User interaction
- None
- Scope
- Changed
- Confidentiality
- High
- Integrity
- High
- Availability
- High
CVSS:3.1/AV:L/AC:H/PR:H/UI:N/S:C/C:H/I:H/A:H
Am I affected? How to checkSteps we derive from the advisory and the affected-version data, so you can decide whether this CVE reaches your setup. They are a guide, not a scan — your own configuration is the authority.
dbcve checksWork through these to decide whether this CVE applies to you.
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Check UEFI firmware versionAccess UEFI/BIOS setup during boot (typically DEL, F2, or F12 key) and navigate to the Main or Information section to view the firmware version. Alternatively, use 'dmidecode -s bios-version' on Linux or 'wmic bios get smbiosbiosversion' on Windows.Affected if The installed firmware version is lower than the vendor's patched version for CVE-2025-4277 (verify against vendor security advisory).
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Verify TCG/TPM is enabledIn UEFI setup, navigate to Security or Advanced settings and check if Trusted Platform Module (TPM) or TCG is enabled. On Windows, run 'tpm.msc' or 'Get-Tpm' PowerShell cmdlet. On Linux, check '/sys/class/tpm*' or use 'tpm2_getcap -c properties-supported'.Affected if TPM/TCG is enabled - the Tcg2Smm driver is active only when TCG functionality is present, making the vulnerability potentially exploitable.
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Confirm Tcg2Smm driver is loadedOn Linux, check UEFI variable for Tcg2Smm presence: 'efivar -l | grep -i tcg2smm' or examine UEFI boot logs. On Windows, check System Information (msinfo32) under 'UEFI' or check 'bcdedit /enum all' for SMM driver entries.Affected if The Tcg2Smm SMM driver is present and listed in UEFI boot configuration - indicates the vulnerable component is installed.
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Check for SMM configuration changesIn UEFI setup under Security or Advanced options, review System Management Mode (SMM) configuration settings. On Windows Server, use 'msinfo32' to check SMM status. On Linux, examine 'dmesg | grep -i smm' after boot for SMM-related messages.Affected if SMM is unlocked or unrestricted in UEFI settings - provides attack surface for the memory corruption vulnerability.
You are affected if your UEFI firmware version is below the vendor's patched version AND TCG/TPM is enabled, allowing the Tcg2Smm driver to load and expose the SMM memory corruption vulnerability.
Generated from the published advisory. Verify against your own configuration.
Remediation Closing itWhat it takes to close this. Where a vendor fix exists we point at it; where none exists we say so plainly, and can build one. Effort estimates are scoped from the advisory, not from your codebase.
From vendor dataApply vendor-supplied firmware/UEFI updates that patch the Tcg2Smm SMM driver. Verify SMM functionality remains operational after patching and ensure no regression in TPM services.
- Consultation6.0 h
- Implementation4.0 h
- Testing8.0 h
- Review / QA4.0 h
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Free · runs locallyCheck whether your project pulls in CVE-2025-4277 — or any other known-vulnerable package — straight from your lock files. Free and open source; it runs locally and uploads nothing.
References Go to the primary sourcePrimary sources — vendor advisories, patches and trackers. Where our summary and a reference disagree, the reference wins.
Primary sourcesPractitioner notes
ContributedPeer-ranked notes from engineers who’ve handled CVE-2025-4277 in production — separate from our analysis above.
The advisory tells you what broke. It rarely tells you what actually worked. If you’ve dealt with this one, that detail is what the next engineer is searching for.
- The version that genuinely resolved it — not the one the vendor claimed
- A config change or rule that shut the vector down
- A gotcha in the upgrade path that cost you an afternoon
No notes yet
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- Version or environment caveats, and links to real fixes
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