Security readout for executives and security teams
Plain-English summary
This Windows flaw can let an attacker already able to run code on a computer gain SYSTEM-level control. That could expose or alter data, enable software installation, or create fully privileged accounts. CISA KEV inclusion indicates known exploitation, making affected systems a high priority.
Executive priority
Prioritize remediation because known exploitation can turn an existing low-privileged foothold into complete Windows system control. Patch deployment must be paired with shadow-copy removal; treating installation alone as completion leaves residual risk.
Technical view
Overly permissive ACLs on multiple system files, including the SAM database, permit local elevation from existing code execution to SYSTEM privileges. The issue has CVSS 3.1 score 7.8 and requires local access with low privileges, but no user interaction. Installing the security update alone does not fully mitigate existing vulnerable shadow copies.
Likely exposure
Exposure applies to the listed Windows 10 versions 1809, 1909, 2004, 20H2, and 21H1. Risk is greatest where an attacker has already gained low-privileged code execution. The supplied evidence does not establish exposure for other Windows releases.
Exploitation context
CVE-2021-36934 appears in CISA's Known Exploited Vulnerabilities catalog, supporting known exploitation. The supplied sources provide no campaign, threat-actor, prevalence, or exploit-chain details. Exploitation requires the attacker to execute code on the victim system first.
Researcher notes
The vulnerability is local, low-complexity, requires low privileges, and needs no user interaction. Impact spans confidentiality, integrity, and availability. The bundle identifies permissive ACLs and SAM exposure but supplies no CWE, complete affected-file list, exploit telemetry, or campaign details.
Mitigation direction
- Install the applicable Microsoft security update for each affected Windows system.
- Manually delete all system-file shadow copies, including SAM copies, as Microsoft directs.
- Follow Microsoft KB5005357 guidance to ensure mitigation is complete.
- Check Microsoft guidance for current or superseding updates before remediation.
Validation and detection
- Inventory systems running the specifically listed Windows 10 versions.
- Verify the applicable Microsoft security update is installed successfully.
- Confirm vulnerable system-file shadow copies were manually removed after updating.
- Reassess affected systems against current Microsoft and CISA guidance.
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.
Execution behavior lookup
The CVE wording references code or command execution, so execution technique review may help defensive triage. This is a Glexia inferred lookup path, not an official MITRE, ATT&CK, or CVE Program mapping.
Open ATT&CK lookupPrivilege 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 lookupDatabase behavior lookup
The CVE wording references database injection or access, so collection and exfiltration review may help. This is a Glexia inferred lookup path, not an official MITRE, ATT&CK, or CVE Program mapping.
Open ATT&CK lookupCVE-2021-36934 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
- Yes
- Published
Vector: CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H/E:F/RL:T/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.
CISA KEV status
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:H/E:F/RL:T/RC:C1.85.9microsoftVulnerability 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:F/RL:T/RC:C
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.
- Added to KEVCISA-ADP
CISA Known Exploited Vulnerabilities metadata lists this CVE as known exploited.
- ADP timelineCISA-ADP
CVE-2021-36934 added to CISA KEV
- CVE updatedCVE Program
The CVE record metadata indicates this as the latest update time.
ADP provider summaries
- 2022-02-10T00:00:00.000Z: CVE-2021-36934 added to CISA KEV
Source materials
- CVE List V5 sourceCVE List V5
- Windows Elevation of Privilege VulnerabilityCVE reference, microsoft · vendor-advisory, patch
- https://www.kb.cert.org/vuls/id/506989CVE reference, CVE
- https://portal.msrc.microsoft.com/en-US/security-guidance/advisory/CVE-2021-36934CVE reference, CVE · x_refsource_MISC, x_transferred
- https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2021-36934CVE reference, CISA-ADP · government-resource
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.