CVE-2025-62864

Secure-partition memory corruption via malformed SMC call

Published Dec 16, 2025 · Updated Dec 16, 2025

Out-of-bounds write in AmpereOne AC03, AC04, and M firmware allows local users to corrupt UEFI-MM Secure Partition memory. The MMCommunicate service accepts an incorrectly formed Secure Monitor Call and writes outside its intended buffer in the protected UEFI-MM context. Affected firmware is before 3.5.9.3 on AC03, before 4.4.5.2 on AC04, and before 5.4.5.1 on M; access requires local high privileges.

CVSS severity4.6
Medium
EPSS probability0.36%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Out-of-bounds write in AmpereOne AC03, AC04, and M firmware allows local users to corrupt UEFI-MM Secure Partition memory. The MMCommunicate service accepts an incorrectly formed Secure Monitor Call and writes outside its intended buffer in the protected UEFI-MM context. Affected firmware is before 3.5.9.3 on AC03, before 4.4.5.2 on AC04, and before 5.4.5.1 on M; access requires local high privileges.

The record

CVE
CVE-2025-62864
Published
Dec 16, 2025
Updated
Dec 16, 2025
Vendor
Unknown vendor
Product
Unknown product
Classifications
CWE-787, T1068
Attack vector
local
Privileges
admin

Timeline

How it unfolded

  1. Dec 16, 2025CVE publishedPublication date reported by the CVE source.
  2. Dec 16, 2025Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Affected buildAffected product and version details are unavailable.

What conditions does exploitation require?

Attack vectorlocal
Required privilegesadmin

What is affected?

Affected products and versions are unavailable in this record.

Published CVSS scores

9.8CISA-ADPCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
4.6Ampere ComputingCVSS:3.1/AV:L/AC:L/PR:H/UI:N/S:C/C:N/I:L/A:L

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

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No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectorlocal
Privilegesadmin
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-787Out-of-bounds Write
T1068Exploitation for Privilege Escalation

Public exploit references

No public exploit references are available in this record.

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Technologies

Your stack

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Your stack

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