Out-of-bounds WriteWeakness · CWE-787

CVE-2025-26403

HIGH · 7.2 CVSS v3.1 Published 2025-08-12
Mitigation only
No fix yet — a mitigation exists. There is no fixed release. A documented workaround reduces exposure in the meantime.
See remediation →
74/100
Remediation priority · Elevated
Zero-click

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 · unedited
Out-of-bounds write in the memory subsystem for some Intel(R) Xeon(R) 6 processors when using Intel(R) SGX or Intel(R) TDX may allow a privileged user to potentially enable escalation of privilege via local access.

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 confidence

Out-of-bounds write vulnerability in the memory subsystem of Intel Xeon 6 processors when Intel SGX or Intel TDX is enabled. A privileged local user may exploit this to achieve privilege escalation.

MitigationApply Intel microcode/firmware updates for affected Xeon 6 processors; contact system vendors for BIOS updates that include the latest Intel microcode. Verify SGX/TDX functionality post-update.

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
None

CVSS:3.1/AV:L/AC:H/PR:H/UI:N/S:C/C:H/I:H/A:N

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 checks

Work through these to decide whether this CVE applies to you.

  1. Identify the CPU model
    Run 'dmidecode -s processor-version' or 'lscpu | grep "Model name"' to determine if the system uses an Intel Xeon 6 processor.
    Affected if The CPU model does not contain "Xeon 6" or a model number in the Xeon 6 series (such as Xeon 6700/6500). The system is NOT affected if a different CPU family is in use.
  2. Verify Intel SGX is enabled
    Check /sys/devices/system/cpu/sgx/enabled; if the file does not exist, SGX may not be supported. Alternatively, run 'cpuid | grep -i sgx' to query CPUID leaf information for SGX capability.
    Affected if The output shows SGX is enabled (value 1) or the CPU supports SGX and it is activatable. If SGX shows as disabled or unavailable, the system is NOT affected by this specific attack vector.
  3. Verify Intel TDX is enabled
    Check for TDX presence via 'dmesg | grep -i tdx' or inspect the TD_INFO MSR (Model Specific Register) using 'rdmsr 0x5' on the executing core if the system runs a TDX-enabled kernel.
    Affected if TDX is detected as active or the system reports TDX capability. If TDX is not present or not enumerated, the system is NOT affected through this attack vector.
  4. Confirm BIOS/UEFI configuration if accessible
    If you have console access, enter the BIOS/UEFI setup during boot and review the Processor or Security settings for Intel SGX and Intel TDX enable/disable states. Alternatively, 'dmidecode' may expose some BIOS-level settings if sufficient privileges exist.
    Affected if Both SGX and TDX are disabled in the BIOS/UEFI. If either technology is enabled, the system falls within the affected configuration scope.

The system is affected only if it runs an Intel Xeon 6 processor AND has either Intel SGX or Intel TDX enabled (or both) in the current configuration.

Generated from the published advisory. Verify against your own configuration.

Check your environment

Paste your version and any relevant configuration and it will be compared against the affected criteria above. Do not include secrets or credentials.

AI-assisted, checked against the advisory. Informational, not a guarantee.

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 data
Mitigation available No clean upgrade yet — mitigate in the meantime
Mitigation

Apply Intel microcode/firmware updates for affected Xeon 6 processors; contact system vendors for BIOS updates that include the latest Intel microcode. Verify SGX/TDX functionality post-update.

Have this fixed Scoped from the published advisory
  • Consultation6.0 h
  • Implementation12.0 h
  • Testing6.0 h
  • Review / QA4.0 h
28.0 hours of engineering $4,980
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Scan for this in your stack

Free · runs locally
dbcve dependency scanner

Check whether your project pulls in CVE-2025-26403 — 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 sources

Practitioner notes

Contributed

Peer-ranked notes from engineers who’ve handled CVE-2025-26403 in production — separate from our analysis above.

No notes yet

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What this is

A place for practitioners to share what actually worked: a mitigation you’ve tested, a configuration change, a version- or environment-specific caveat, or a link to a verified patch. The most useful notes rise to the top as peers upvote them, so the signal stays high.

What belongs here
  • Verified mitigations, workarounds, and config changes
  • Version or environment caveats, and links to real fixes
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