Security readout for executives and security teams
Plain-English summary
This is a Linux kernel information-disclosure flaw in ALSA rawmidi handling. A local user could potentially read a small amount of uninitialized kernel memory through version handling. The business urgency is limited but real on shared Linux systems, multi-user hosts, or environments running untrusted local workloads.
Executive priority
Schedule remediation through normal Linux kernel patch cycles, with higher priority for shared or multi-tenant systems. No source indicates active exploitation, remote compromise, integrity loss, or availability impact.
Technical view
ALSA rawmidi open handling left user_pversion uninitialized because the file private structure was allocated with kmalloc. The CVSS vector is local, low complexity, no privileges, no user interaction, unchanged scope, and low confidentiality impact only. The source notes ALSA sequencer already clears its file structure.
Likely exposure
Exposure is most relevant to Linux systems with affected kernel versions or vulnerable commit ranges and local users or workloads. The source bundle flags Linux 5.15/5.16-era entries and specific kernel commits, but distro backports require vendor confirmation.
Exploitation context
The provided sources do not report active exploitation, and the CVE is not marked KEV. The attack vector is local, with confidentiality impact only. Treat this as a patch-management issue unless your environment has untrusted local users or tenant workloads.
Researcher notes
Focus review on ALSA rawmidi file-open state initialization and whether user_pversion can expose uninitialized memory. The source explicitly says ALSA sequencer clears the file structure, so avoid extending impact to sequencer paths without evidence.
Mitigation direction
- Apply Linux kernel updates containing the referenced stable fixes.
- Use distribution kernel advisories to confirm backported fixes.
- Prioritize shared hosts and systems running untrusted local workloads.
- Track kernel packages until the CVE is closed in asset records.
Validation and detection
- Inventory Linux hosts and kernel versions across the fleet.
- Compare installed kernels with vendor advisories for CVE-2021-47096.
- Check whether kernel changelogs include the referenced stable commits.
- Identify systems allowing local access by untrusted users or workloads.
Public sources used
Generated from the cited source records. This long-tail analysis has not been individually reviewed by a named human.
Conservative CVE-to-ATT&CK context
These mappings and lookup hints may be relevant to the vulnerability behavior, CWE, affected product, or exposure path. Glexia-inferred context is not an official MITRE, ATT&CK, CWE, or CVE Program mapping.
ATT&CK lookup starting points
Use these exact CWE pages and searches to review the Glexia ATT&CK library from this CVE's weakness and description context.
CVE-2021-47096 mapping review
Open the CVE-to-ATT&CK bridge for reviewed, inferred, or future official mappings tied to this CVE.
Open ATT&CK lookup- Severity
- Medium
- CVSS
- 4 (3.1)
- Known Exploited
- No
- Published
Vector: CVSS:3.1/AV:L/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:N
CNA and ADP enrichment extracted from CVE v5
These fields come from the CVE record and ADP containers, not from Glexia's Take. They preserve time-varying source decisions such as CISA SSVC, KEV status, CVSS metrics, and provider references.
SSVC decision data
CVSS vector scores
1 official scoreWe collect every scored CVSS vector available in the official CNA and ADP containers. When more than one version is present, the table keeps the source vectors side by side instead of collapsing them into the highest score.
CVSS:3.1/AV:L/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:N2.51.4CISA-ADPVulnerability scoring details
Base CVSS 3.1 score
4MediumVector: CVSS:3.1/AV:L/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:N
Vulnerability timeline
Timeline events are normalized from CVE metadata, CNA source timelines, ADP timelines, and KEV metadata when present.
- CVE reservedCVE Program
The CVE ID was reserved by the assigning CNA.
- CVE publishedCVE Program
The CVE record was published.
- CVE updatedCVE Program
The CVE record metadata indicates this as the latest update time.
ADP provider summaries
Source materials
- CVE List V5 sourceCVE List V5
- https://git.kernel.org/stable/c/b398fcbe4de1e1100867fdb6f447c6fbc8fe7085CVE reference, Linux
- https://git.kernel.org/stable/c/39a8fc4971a00d22536aeb7d446ee4a97810611bCVE reference, Linux
Products and packages named in the record
CWE details
CWE links open Glexia weakness intelligence pages with official CWE context, developer remediation guidance, and related CVE mappings.