Security readout for executives and security teams
Plain-English summary
This is a Linux kernel memory-safety bug in the virtual CAN network driver. A local user with some privileges could potentially trigger use-after-free behavior, risking system compromise or crash. Business urgency depends on whether vulnerable Linux kernels with vxcan/CAN networking are present.
Executive priority
Treat as high priority for Linux fleets with local multi-user access, container hosts, or CAN/vxcan use. It is not enough to check upstream version numbers; confirm vendor-patched kernels are installed and running.
Technical view
CVE-2021-47669 is a CWE-416 use-after-free in Linux vxcan_xmit. The code accessed skb-backed canfd_frame memory after netif_rx_ni(skb), when dereferencing skb was unsafe. The CVSS 3.1 vector is local, low complexity, low privileges, no user interaction, with high confidentiality, integrity, and availability impact.
Likely exposure
Exposure is most likely on Linux systems running affected kernel ranges where virtual CAN vxcan functionality is available. The source bundle lists Linux kernel versions and stable fix commits, but distribution backports may change exact exposure, so package-level verification is required.
Exploitation context
The source bundle does not show active exploitation, and KEV status is false. The CVSS vector supports local, low-privilege exploitation potential without user interaction, but no public exploit evidence is provided in the supplied sources.
Researcher notes
The key condition is use-after-free after netif_rx_ni(skb) in vxcan transmit handling. The source data identifies stable commits but does not provide a complete distro matrix, exploit proof, or operational mitigation beyond applying corrected kernel code.
Mitigation direction
- Apply Linux kernel updates that include the referenced stable vxcan fixes.
- Check distribution or vendor advisories for backported fixed kernel packages.
- Prioritize systems that allow local users or workloads to access CAN/vxcan networking.
- Use normal change control for kernel updates and reboot requirements.
Validation and detection
- Inventory Linux kernel versions across servers, endpoints, and container hosts.
- Check whether deployed kernels include the referenced stable fix commits or vendor backports.
- Identify systems where vxcan or CAN networking is enabled or available.
- Confirm remediation by verifying the running kernel after reboot.
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-416: 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-2021-47669 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
- High
- CVSS
- 7.8 (3.1)
- Known Exploited
- No
- Published
Vector: CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/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:H/I:H/A:H1.85.9CISA-ADPVulnerability scoring details
Base CVSS 3.1 score
7.8HighVector: CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/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/6d6dcf2399cdd26f7f5426ca8dd8366b7f2ca105CVE reference, Linux
- https://git.kernel.org/stable/c/9b820875a32a3443d67bfd368e93038354e98052CVE reference, Linux
- https://git.kernel.org/stable/c/a24476b37167816e6352ca1a2cf3769847774f70CVE reference, Linux
- https://git.kernel.org/stable/c/e771a874076115df8bff27d325edfd2340e4ec69CVE reference, Linux
- https://git.kernel.org/stable/c/75854cad5d80976f6ea0f0431f8cedd3bcc475cbCVE 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.
Use After Free
Use After Free represents a recurring weakness pattern that can create exploitable paths when design, validation, or implementation controls are missing.