Security readout for executives and security teams
Plain-English summary
CVE-2021-31187 is a Windows WalletService elevation-of-privilege issue. It is not a remote internet-entry bug, but a low-privileged local user or process could potentially gain higher privileges on affected Windows 10 systems. Treat it as important for endpoint hardening, especially where untrusted users or code can run locally.
Executive priority
Patch through normal high-severity endpoint remediation cycles. Escalate for shared or unmanaged Windows 10 systems because local privilege escalation can turn a foothold into broader system control, even without remote exploitability evidence.
Technical view
The CVSS 3.1 vector is 7.8 high: local access, low complexity, low privileges required, no user interaction, unchanged scope, and high confidentiality, integrity, and availability impact. Microsoft identifies affected Windows 10 releases from 1507 through 20H2, with WalletService as the vulnerable component.
Likely exposure
Exposure is limited to affected Microsoft Windows 10 versions listed in the source bundle: 1507, 1607, 1803, 1809, 1909, 2004, and 20H2. Prioritize endpoints, shared workstations, VDI images, and systems where local users or locally executed code are plausible.
Exploitation context
The source bundle does not show CISA KEV listing or active exploitation. The CVSS exploit maturity is unproven, and exploitation requires local access with low privileges. A ZDI advisory exists, but the provided sources do not establish public weaponization or in-the-wild attacks.
Researcher notes
Useful validation is asset and patch-state focused. The bundle lacks root-cause detail, affected binaries, or exploit primitives. Do not assume exploitability beyond local authenticated elevation of privilege in WalletService on the listed Windows 10 versions.
Mitigation direction
- Apply Microsoft security updates or guidance for CVE-2021-31187 from MSRC.
- Inventory Windows 10 systems against the affected versions and builds.
- Prioritize shared, kiosk, VDI, and high-privilege-adjacent endpoints.
- Restrict local interactive access where business need is weak.
- Monitor Microsoft guidance for supersedence or lifecycle caveats.
Validation and detection
- Confirm Windows version and build against the affected list.
- Verify the relevant Microsoft update level is installed.
- Check endpoint management coverage for unsupported or unmanaged Windows 10 assets.
- Review local privilege boundary controls on shared systems.
- Document exceptions with owner, exposure, and remediation date.
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.
Privilege behavior lookup
The CVE wording references privilege impact, so privilege escalation and authorization behavior review may help. This is a Glexia inferred lookup path, not an official MITRE, ATT&CK, or CVE Program mapping.
Open ATT&CK lookupCVE-2021-31187 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/E:U/RL:O/RC:C
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 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:H/E:U/RL:O/RC:C1.85.9Primary CVE scoreVulnerability 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/E:U/RL:O/RC:C
Source materials
- CVE List V5 sourceCVE List V5
- https://portal.msrc.microsoft.com/en-US/security-guidance/advisory/CVE-2021-31187CVE reference · x_refsource_MISC
- https://www.zerodayinitiative.com/advisories/ZDI-21-571/CVE 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.