Security readout for executives and security teams
Plain-English summary
CVE-2021-47367 is a Linux kernel virtio-net flaw where unused memory pages were not released in a specific packet-building path. The source rates it medium severity with local, low-complexity access required. Business urgency is highest for Linux systems using virtio networking, especially virtualized servers or hosts running affected kernel versions.
Executive priority
Treat this as a routine but real kernel remediation item, not an emergency. Prioritize patching internet-facing, multi-user, or virtualization-heavy Linux environments during the next kernel maintenance cycle, unless vendor guidance raises severity for your distribution.
Technical view
The vulnerable virtio-net path tries build_skb() when tailroom is sufficient, but in big mode it failed to release unused pages chained through private data. The CVE source lists CWE-119 and CVSS 3.1 score 5.5 with local attack vector, low complexity, low privileges, no user interaction, and high confidentiality impact.
Likely exposure
Exposure is most likely on Linux systems using the virtio-net driver with affected kernels. The bundle identifies Linux kernel 5.13-era versions and fixed stable references around 5.14.9 and 5.15, plus specific kernel stable commits. Exact distribution package impact requires vendor mapping.
Exploitation context
The source bundle does not show CISA KEV listing or public active exploitation evidence. The CVSS vector requires local access and low privileges, with no user interaction. No exploit technique or weaponized details are provided in the cited sources.
Researcher notes
Evidence is limited to the CVE record and two Linux stable commit references. The description supports a virtio-net page-release bug in big mode; it does not provide exploit details, affected distribution packages, or operational mitigations beyond applying fixed kernels.
Mitigation direction
- Check kernel vendor advisories for CVE-2021-47367 applicability.
- Upgrade affected Linux kernels to versions containing the referenced stable fixes.
- Prioritize virtualized Linux systems using virtio-net networking.
- Apply distribution-provided kernel packages rather than hand-applying commits when possible.
- Track unresolved systems through normal vulnerability management exceptions.
Validation and detection
- Inventory Linux kernel versions across virtualized and cloud workloads.
- Identify hosts or guests using the virtio-net driver.
- Compare running kernels with vendor-fixed versions for CVE-2021-47367.
- Confirm whether kernel builds include the cited stable commits.
- Document systems not using virtio-net as lower exposure.
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-119: 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-2021-47367 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:H/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:L/UI:N/S:U/C:H/I:N/A:N1.83.6CISA-ADPVulnerability scoring details
Base CVSS 3.1 score
5.5MediumVector: CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/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/f020bb63b5d2e5576acadd10e158fe3b04af67baCVE reference, Linux
- https://git.kernel.org/stable/c/afd92d82c9d715fb97565408755acad81573591aCVE 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.