CVE-2024-21977

Incomplete cleanup after loading a CPU microcode patch may allow a privileged attacker to degrade the entropy of the RDRAND instruction, potentially resulting in loss of integrity for SEV-SNP guests.

Published: 2025-09-05 Last update: 2026-06-17 Assigner: [email protected] Source: [email protected]
NVD Status：Deferred，CVE State: published
View at NVD, CVE.org, EUVD

CVE-2024-21977 is rated Low Risk (14.2/100): CVSS Low severity, with low exploitation likelihood (EPSS 0.14%). Low composite risk—no urgent action required; patch on your normal maintenance cycle and revisit priority if CVSS or EPSS increases.

Risk is dynamic; we continuously reassess and refresh what is shown on this page as upstream context changes.

Exploit prediction scoring system (EPSS) score for CVE-2024-21977

EPSS lead: Daily EPSS estimates relative likelihood of exploitation; percentile ranks this CVE among scored vulnerabilities (higher = more severe relative rank).

# Date Old EPSS score New EPSS score Delta (New - Old)
1 2026-06-15 0.01% 0.14% +0.13%
2 2025-09-06 — 0.01% —

Full EPSS history (2 records total)

Common vulnerability scoring system (CVSS) metrics for CVE-2024-21977

CVSS metrics for this CVE.

Base score Version Severity Vector Exploitability Impact Score source
3.2 3.1 LOW
CVSS:3.1/AV:L/AC:L/PR:H/UI:N/S:C/C:N/I:L/A:N Click to expand
Attack vector (AV:L)
They already need access on the box, or another person has to do something wrong; it’s not a remote drive-by.
Attack complexity (AC:L)
Once they can reach the bug, pulling it off is straightforward—no weird race conditions or rare setup.
Privileges required (PR:H)
They need powerful rights—admin, root, or similar—before this pays off.
User interaction (UI:N)
Nobody has to click “OK” or open a trap file; it can work without a victim helping.
Scope (S:C)
Breaking this can reach past the original component and bite other resources—bigger blast radius.
Confidentiality (C:N)
Doesn’t really leak secrets in a meaningful way.
Integrity (I:L)
Attackers could change some data, but it’s limited—not everything goes.
Availability (A:N)
Service keeps running; no real outage angle.
 1.5 1.4 [email protected]

Weakness enumeration for CVE-2024-21977

Affected software / configurations for CVE-2024-21977

Vendor Product Version Raw CPE
No affected products in dataset.

References for CVE-2024-21977

cvelogic Threat Intelligence