Security readout for executives and security teams
Plain-English summary
This CVE is a Linux kernel crash condition in the MediaTek mt7921 wireless driver. If firmware is missing or fails to download, affected kernels can panic instead of failing cleanly. The business impact is availability loss on systems using that hardware and driver, not confirmed data theft or remote compromise.
Executive priority
Treat this as a targeted availability risk. It deserves routine patching where MT7921 hardware exists, faster action for devices where reboot loops or loss of Wi-Fi would disrupt operations.
Technical view
The mt76 mt7921 PCI probe path can mishandle cleanup after firmware download failure, reaching a kernel BUG in MSI IRQ cleanup and causing a fatal exception. The source lists Linux kernel 5.12-era versions as affected and references stable kernel fixes.
Likely exposure
Exposure is most likely on Linux systems with MediaTek MT7921 Wi-Fi hardware using the mt7921e driver, especially kernels in the affected 5.12 range. Distro backports may change exposure, so kernel package advisories matter.
Exploitation context
The provided sources do not show active exploitation, KEV listing, public exploit code, or remote attack details. The demonstrated trigger is firmware missing or firmware download failure during driver initialization, causing denial of service through kernel panic.
Researcher notes
Evidence is limited to the CVE record and upstream stable commits. No CVSS, CWE, exploitability detail, or vendor-specific package matrix is provided. Avoid assuming remote reachability; validate exposure through hardware, driver, firmware, and distro kernel mapping.
Mitigation direction
- Apply vendor or distribution kernel updates containing the referenced stable fixes.
- Verify affected systems have the required mt7921 firmware installed and loading correctly.
- Prioritize laptops, appliances, or embedded Linux devices using MediaTek MT7921 Wi-Fi.
- Check vendor guidance before applying workarounds not documented by maintainers.
Validation and detection
- Inventory Linux kernel versions and identify systems using the mt7921e driver.
- Review boot logs for mt7921 firmware download failures or kernel panic traces.
- Confirm distribution advisories map the referenced upstream fixes into installed packages.
- Test patched systems for clean boot and functional Wi-Fi initialization.
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-2021-47027 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
- Unknown
- CVSS
- Not scored
- Known Exploited
- No
- Published
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
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/a46b536cd60c0dbd4bf767c62a8774dec52bf099CVE reference, Linux
- https://git.kernel.org/stable/c/e230f0c44f011f3270680a506b19b7e84c5e8923CVE 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.