CVE-2024-56161

Publication date 3 February 2025

Last updated 2 February 2026

Ubuntu priority

Medium

Why this priority?

Cvss 3 Severity Score

7.2 · High

Score breakdown

Description

Improper signature verification in AMD CPU ROM microcode patch loader may allow an attacker with local administrator privilege to load malicious CPU microcode resulting in loss of confidentiality and integrity of a confidential guest running under AMD SEV-SNP.

Read the notes from the security team

Status

Package Ubuntu Release Status
amd64-microcode 25.04 plucky
Fixed 3.20250311.1ubuntu0.25.04.1
24.10 oracular
Fixed 3.20250311.1ubuntu0.24.10.1
24.04 LTS noble
Fixed 3.20250311.1ubuntu0.24.04.1
22.04 LTS jammy
Not affected
20.04 LTS focal
Not affected
18.04 LTS bionic
Not affected
16.04 LTS xenial
Not affected
14.04 LTS trusty
Not affected

Notes

rodrigo-zaiden

This CVE is inside the bucket of two CVEs (CVE-2024-56161 and CVE-2024-36347) known as "EntrySign", the AMD Zen microcode signature validation vulnerability, affecting Zen 1/2/3/4/5 platforms. This CVE specifically tracks the AMD SEV-SNP firmware that exists in amd64-microcode package. The fix for this CVE doesn't fix EntrySign but updates the AMD SEV firmware based on AMD-SB-3019 mitigations, which is basically an update to support SEV-SNP attestation on updated firmware systems. The complete fix for EntrySign comprehends a BIOS upgrade (distributed through OEMs) that will properly fix microcode signature verification, and because of that it is not possible to distribute the fix through OS-level updates (such as amd64-microcode package). AMD SEV firmware were included in noble onwards, based on upstream release 20220411, releases older than that are not supported.

Patch details

For informational purposes only. We recommend not to cherry-pick updates. How can I get the fixes?

Package Patch details
amd64-microcode

Severity score breakdown

Parameter Value
Base score 7.2 · High
Attack vector Local
Attack complexity High
Privileges required High
User interaction None
Scope Changed
Confidentiality High
Integrity impact High
Availability impact None
Vector CVSS:3.1/AV:L/AC:H/PR:H/UI:N/S:C/C:H/I:H/A:N

References

Related Ubuntu Security Notices (USN)

    • USN-7560-1
    • AMD Microcode vulnerability
    • 9 June 2025
    • USN-7561-1
    • AMD Microcode vulnerabilities
    • 9 June 2025

Other references