Security readout for executives and security teams
Plain-English summary
This CVE affects specific Buffalo Wi-Fi routers. Vulnerable firmware can let an attacker run operating-system commands as root, which means full control of the device. The public bundle does not describe the attack path, exploit status, CVSS score, or a named fixed version.
Executive priority
Prioritize remediation for affected routers, especially if they protect offices, remote sites, or sensitive networks. Root-level compromise of a router can undermine network trust, traffic routing, and downstream security controls.
Technical view
CVE-2021-20731 covers arbitrary OS command execution with root privileges in Buffalo WSR-1166DHP3 firmware Ver.1.16 and prior, and WSR-1166DHP4 firmware Ver.1.02 and prior. The vector is unspecified in the supplied CVE description, limiting exposure validation detail.
Likely exposure
Exposure is limited to Buffalo WSR-1166DHP3 and WSR-1166DHP4 devices running the listed vulnerable firmware versions. The bundle does not prove whether exploitation requires LAN access, WAN exposure, authentication, or administrator interaction.
Exploitation context
The source bundle does not report active exploitation, and the CVE is not marked as CISA KEV. Because the issue allows root-level command execution, exposed or unmanaged devices should still be treated as materially risky.
Researcher notes
The public bundle lacks CVSS, CWE, prerequisites, affected interfaces, payload details, and fixed-version data. Treat the vector as unknown and avoid assumptions about exploitability beyond the stated root command-execution impact.
Mitigation direction
- Inventory Buffalo WSR-1166DHP3 and WSR-1166DHP4 devices in use.
- Check installed firmware versions against the affected version ranges.
- Review Buffalo and JVN guidance for fixed firmware or official remediation.
- Restrict router management access while remediation is confirmed.
- Replace devices if vendor-supported firmware is unavailable.
Validation and detection
- Confirm device model and firmware from administrative inventory or device console.
- Check whether router management interfaces are reachable from untrusted networks.
- Review router logs for unexplained configuration changes or reboots.
- Document remediation status for each affected router.
- Recheck vendor advisories before closing the finding.
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-2021-20731 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.
CVSS and timeline data
No CVSS vectors or timeline events were available in the normalized CVE source material.
Source materials
- CVE List V5 sourceCVE List V5
- https://www.buffalo.jp/news/detail/20210531-01.htmlCVE reference · x_refsource_MISC
- https://jvn.jp/en/vu/JVNVU92862829/index.htmlCVE reference · x_refsource_MISC
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.