CyberSecBulletin
CVE-2024-21978NVD status: Analyzed

Improper input validation in SEV-SNP could allow a malicious hypervisor to read or overwrite…

Published Updated By the CyberSecBulletin desk

CVE-2024-21978 is a high-severity improper input validation vulnerability in 3rd Gen AMD EPYC™ Processors from AMD, with a CVSS 3.1 base score of 7.9 out of 10. It can be exploited with local access to the system by an attacker with administrator privileges, without any action from a user. The record lists version MilanPI 1.0.0.D as the first without the flaw, so updating 3rd Gen AMD EPYC™ Processors to that release or later removes the exposure. There is no confirmed exploitation so far. EPSS estimates a 0.49% chance of exploitation within 30 days, which is low compared with other CVEs.

Next patch cycle

High severity with no evidence of exploitation so far.

What to do

  1. Update 3rd Gen AMD EPYC™ Processors to MilanPI 1.0.0.D or a later version.
  2. Update 4th Gen AMD EPYC™ Processors to GenoaPI 1.0.0.C or a later version.
  3. Update AMD EPYC™ Embedded 7003 to EmbMilanPI-SP3 1.0.0.9 or a later version.

Affected products and versions

VendorProductAffected versionsFixed in
AMD3rd Gen AMD EPYC™ Processorsvarious up to, but not including, MilanPI 1.0.0.DMilanPI 1.0.0.D
AMD4th Gen AMD EPYC™ Processorsvarious up to, but not including, GenoaPI 1.0.0.CGenoaPI 1.0.0.C
AMDAMD EPYC™ Embedded 7003various up to, but not including, EmbMilanPI-SP3 1.0.0.9EmbMilanPI-SP3 1.0.0.9
AMDAMD EPYC™ Embedded 9003various up to, but not including, EmbGenoaPI-SP5 1.0.0.7EmbGenoaPI-SP5 1.0.0.7
AMDepyc_7003_firmwarebefore milanpi_1.0.0.9_sp3milanpi_1.0.0.9_sp3
AMDepyc_9003_firmwarebefore genoapi_1.0.0.7_sp5genoapi_1.0.0.7_sp5
AMDepyc_7773x_firmwarebefore milanpi_1.0.0.dmilanpi_1.0.0.d
AMDepyc_9754s_firmwarebefore genoapi_1.0.0.cgenoapi_1.0.0.c
AMDEpyc 7203 Firmwarebefore milanpi_1.0.0.dmilanpi_1.0.0.d
AMDEpyc 7203p Firmwarebefore milanpi_1.0.0.dmilanpi_1.0.0.d
AMDEpyc 72f3 Firmwarebefore milanpi_1.0.0.dmilanpi_1.0.0.d
AMDEpyc 7303 Firmwarebefore milanpi_1.0.0.dmilanpi_1.0.0.d
AMDEpyc 7303p Firmwarebefore milanpi_1.0.0.dmilanpi_1.0.0.d
AMDEpyc 7313 Firmwarebefore milanpi_1.0.0.dmilanpi_1.0.0.d
AMDEpyc 7313p Firmwarebefore milanpi_1.0.0.dmilanpi_1.0.0.d
AMDEpyc 7343 Firmwarebefore milanpi_1.0.0.dmilanpi_1.0.0.d
AMDEpyc 73f3 Firmwarebefore milanpi_1.0.0.dmilanpi_1.0.0.d
AMDEpyc 7373x Firmwarebefore milanpi_1.0.0.dmilanpi_1.0.0.d
AMDEpyc 7413 Firmwarebefore milanpi_1.0.0.dmilanpi_1.0.0.d
AMDEpyc 7443 Firmwarebefore milanpi_1.0.0.dmilanpi_1.0.0.d
AMDEpyc 7443p Firmwarebefore milanpi_1.0.0.dmilanpi_1.0.0.d
AMDEpyc 74f3 Firmwarebefore milanpi_1.0.0.dmilanpi_1.0.0.d
AMDEpyc 7453 Firmwarebefore milanpi_1.0.0.dmilanpi_1.0.0.d
AMDEpyc 7473x Firmwarebefore milanpi_1.0.0.dmilanpi_1.0.0.d
AMDEpyc 7513 Firmwarebefore milanpi_1.0.0.dmilanpi_1.0.0.d

Version data comes from the organisation that assigned the CVE; 35 further products are omitted here. Confirm against the vendor advisory before deciding you are unaffected.

How the severity score breaks down

Attack vector
LocalThe attacker needs local access or must trick a user into running something.
Attack complexity
LowNo special conditions are needed; the attack works reliably.
Privileges required
HighAdministrator-level access is required first.
User interaction
NoneNo action by a victim is required.
Scope
ChangedThe attack can reach beyond the vulnerable component into other systems.
Confidentiality
HighAll data handled by the component can be read.
Integrity
HighData or code can be modified at will.
Availability
NoneAvailability is not affected.

Vector: CVSS:3.1/AV:L/AC:L/PR:H/UI:N/S:C/C:H/I:H/A:N. Scored by NVD.

Scoring systemScoreSeverityScored by
CVSS 3.16.0MediumCNA (amd.com)
CVSS 3.17.9HighNVD

Official description

Improper input validation in SEV-SNP could allow a malicious hypervisor to read or overwrite guest memory potentially leading to data leakage or data corruption.

Source: the CVE record as published by its numbering authority, via NVD and CVE.org.

The underlying weakness: Improper Input Validation

The product receives input or data, but it does not validate or incorrectly validates that the input has the properties that are required to process the data safely and correctly.

How developers prevent this class of flaw

  • Consider using language-theoretic security (LangSec) techniques that characterize inputs using a formal language and build recognizers for that language. This effectively requires parsing to be a distinct layer that effectively enforces a boundary between raw input and internal data representations, instead of allowing parser code to be scattered throughout the program, where it could be subject to errors or inconsistencies that create weaknesses.
  • Use an input validation framework such as Struts or the OWASP ESAPI Validation API. Note that using a framework does not automatically address all input validation problems; be mindful of weaknesses that could arise from misusing the framework itself (CWE-1173).
  • Understand all the potential areas where untrusted inputs can enter the product, including but not limited to: parameters or arguments, cookies, anything read from the network, environment variables, reverse DNS lookups, query results, request headers, URL components, e-mail, files, filenames, databases, and any external systems that provide data to the application. Remember that such inputs may be obtained indirectly through API calls.

More Improper Input Validation vulnerabilities (CWE-20)

Timeline

  1. CVE record published.
  2. CISA published its SSVC assessment (exploitation: none, automatable: no, technical impact: total).
  3. Record last changed materially (score, affected products, status or references).

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