Security readout for executives and security teams
Plain-English summary
This is a Linux kernel availability bug in the virtio GPU driver. A local authenticated user could trigger a crash if an allocation path fails and cleanup handles a NULL object list incorrectly. The reported impact is denial of service only, not data theft or privilege escalation.
Executive priority
Treat this as a routine but real availability risk. It is not currently evidenced as exploited and needs local access, but systems hosting untrusted users or virtualized workloads should receive normal kernel patch priority.
Technical view
CVE-2021-47657 is a CWE-476 NULL pointer dereference in drm/virtio. If virtio_gpu_object_shmem_init() fails, virtio_gpu_array_put_free() may receive objs == NULL. The fix adds a NULL check and returns. CVSS 3.1 is 5.5, local attack vector, low complexity, low privileges, and high availability impact.
Likely exposure
Exposure is most relevant to Linux systems running affected kernel versions with the virtio GPU DRM driver reachable. This commonly matters for virtualized Linux guests using virtio-gpu. The source bundle lists affected Linux versions and upstream stable fix commits but does not provide distribution-specific package status.
Exploitation context
The source bundle does not show active exploitation, and KEV status is false. The vulnerability requires local privileges and affects availability. The underlying trigger involves a failure path, reported via syzbot fault injection, so real-world exploitability is not established by the provided sources.
Researcher notes
The evidence supports a local denial-of-service assessment only. The CVE record identifies affected upstream Linux versions and four stable commits. It does not identify exploitation in the wild, affected distributions, or additional impacts beyond availability.
Mitigation direction
- Apply a kernel update containing the referenced upstream stable fixes.
- Check your Linux distribution advisory for backported package status.
- Prioritize shared or multi-user virtualized Linux systems using virtio-gpu.
- Limit untrusted local shell access where affected kernels remain deployed.
- Avoid driver configuration changes unless validated by your OS vendor.
Validation and detection
- Inventory Linux kernel versions against the affected versions in the CVE record.
- Confirm whether virtio GPU DRM support is enabled or loaded.
- Check distro changelogs for the referenced stable commit backports.
- Review kernel logs for virtio-gpu related NULL dereference crashes.
- Verify patched kernels include the NULL guard in virtio_gpu_array_put_free().
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.
CWE-476: Exact CWE lookup
Use the exact CWE identifier as the starting point before reviewing related ATT&CK behavior. Open the exact CWE lookup page first, then review the ATT&CK searches from that MITRE weakness context. This is a Glexia lookup hint, not an official ATT&CK mapping.
Open ATT&CK lookupCVE-2021-47657 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
- 5.5 (3.1)
- Known Exploited
- No
- Published
Vector: CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
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:L/UI:N/S:U/C:N/I:N/A:H1.83.6CISA-ADPVulnerability scoring details
Base CVSS 3.1 score
5.5MediumVector: CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
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/b094fece3810c71ceee6f0921676cb65d4e68c5aCVE reference, Linux
- https://git.kernel.org/stable/c/ac92b474eeeed75b8660374ba1d129a121c09da8CVE reference, Linux
- https://git.kernel.org/stable/c/abc9ad36df16e27ac1c665085157f1a082d39bacCVE reference, Linux
- https://git.kernel.org/stable/c/6b79f96f4a23846516e5e6e4dd37fc06f43a60ddCVE 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.