5.5

CVE-2021-47008: linux NULL Pointer Dereference

CVSS: 5.5v3.1MediumAnalyzed
AliasesUBUNTU-CVE-2021-47008
Published 28-02-2024Last modified 11-05-2026
Open JSON

Vulnerability summary

CVE-2021-47008 is a medium (CVSS 5.5) NULL Pointer Dereference vulnerability in linux. EPSS estimates a 0.24% chance of exploitation in the next 30 days, higher than 13.5% of scored vulnerabilities.

Overall risk
22/100
0100
Low · default modelHow is this calculated?
CVSS score
5.5/10
010
Medium · v3.1 (NVD)
EPSS score
0.24%
0%100%
Low · 0.00 pp in 30 days
KEVNot listedIn no KEV catalog
RansomwareNone recordedNo known use recorded
Public exploits0No public exploits recorded

Timeline

  1. 28-02-2024
    PublishedVulnerability first disclosed.
  2. 11-05-2026
    Last modifiedVulnerability information updated.

Description

In the Linux kernel, the following vulnerability has been resolved: KVM: SVM: Make sure GHCB is mapped before updating Access to the GHCB is mainly in the VMGEXIT path and it is known that the GHCB will be mapped. But there are two paths where it is possible the GHCB might not be mapped. The sev_vcpu_deliver_sipi_vector() routine will update the GHCB to inform the caller of the AP Reset Hold NAE event that a SIPI has been delivered. However, if a SIPI is performed without a corresponding AP Reset Hold, then the GHCB might not be mapped (depending on the previous VMEXIT), which will result in a NULL pointer dereference. The svm_complete_emulated_msr() routine will update the GHCB to inform the caller of a RDMSR/WRMSR operation about any errors. While it is likely that the GHCB will be mapped in this situation, add a safe guard in this path to be certain a NULL pointer dereference is not encountered.

CVSS metrics

2 scores · 2 sources · 1 version

EPSS trend

Probability

0.24%

Chance of exploitation in the next 30 days

Percentile

14%

Versus all other CVEs

30-day change

0.00 pp

From 0.24% on 19-09-2026

19-09-202619-10-2026
EPSS score
0.24%

Known exploited

Compare KEV catalogs

Not in any of the 3 tracked catalogs.

Public exploits

0 found

No public exploits indexed.

Weaknesses

CWE · root cause

Affected systems

Ubuntu62 products
  • linux-allwinner-5.19All versions (No fix recorded)
  • linux-aws-5.0All versions (No fix recorded)
  • linux-aws-5.11All versions (No fix recorded)
  • linux-aws-5.13All versions (No fix recorded)
  • linux-aws-5.19All versions (No fix recorded)
Linux2 products
  • linux≥ f1c6366e304328de301be362eca905a3503ff33b, < fb9e14f4f8217a0980f8da2c8ff70dee058cbe47 | ≥ f1c6366e304328de301be362eca905a3503ff33b, < fd722a57fe0b80133dacae4e1c852ee4212f9b2e | ≥ f1c6366e304328de301be362eca905a3503ff33b, < a3ba26ecfb569f4aa3f867e80c02aa65f20aadad | 5.11
  • linux_kernel≥ 5.11, < 5.11.22 | ≥ 5.12, < 5.12.5

2 vendors · 64 products

References

6 links