Security readout for executives and security teams
Plain-English summary
CVE-2021-21791 is a local information disclosure flaw in the driver used by IOBit Advanced SystemCare Ultimate 14.2.0.220. A low-privileged user could trigger privileged I/O reads and potentially expose sensitive kernel or device data. It is not a remote takeover issue, but it matters on shared or compromised endpoints.
Executive priority
Treat this as a moderate endpoint hardening issue. It is unlikely to be the initial breach vector, but it could help an attacker already on a machine gather sensitive low-level data. Prioritize exposed shared systems and remove unnecessary consumer utility drivers from managed environments.
Technical view
The vulnerability is tied to handling of privileged I/O read requests through a crafted IRP. Talos states the IN instruction can read two bytes from a specified I/O device, leaking sensitive device data to unprivileged users. CVSS 6.5 reflects local access, low complexity, low privileges, no user interaction, changed scope, and high confidentiality impact.
Likely exposure
Exposure is limited to systems running IOBit Advanced SystemCare Ultimate 14.2.0.220 with the affected driver present. Risk is higher on multi-user Windows systems, shared workstations, or endpoints where attackers may already have low-privileged code execution.
Exploitation context
The provided sources do not show CISA KEV listing or active exploitation. The described attack context is local: a low-privileged user sends a specially crafted I/O request packet to the vulnerable driver to cause privileged reads.
Researcher notes
The source bundle identifies CWE-782 and a confidentiality-only impact. Evidence is strongest for the vulnerable version and driver behavior, but incomplete for vendor fix status, exploit availability, or affected version ranges beyond 14.2.0.220. Avoid assuming broader IOBit product exposure without vendor confirmation.
Mitigation direction
- Inventory endpoints for IOBit Advanced SystemCare Ultimate 14.2.0.220 and its driver.
- Check IOBit or Talos guidance for fixed versions or vendor-recommended remediation.
- Remove or disable the affected software where it is not business-required.
- Limit local interactive access on systems where the affected driver is present.
- Prioritize remediation on shared, kiosk, developer, and high-value administrative endpoints.
Validation and detection
- Confirm whether Advanced SystemCare Ultimate 14.2.0.220 is installed on Windows endpoints.
- Verify whether the associated driver remains loaded after uninstall or upgrade attempts.
- Review endpoint telemetry for unexpected access to the affected driver interface.
- Validate remediation by confirming the vulnerable version and driver are absent.
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-782: 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-2021-21791 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
- 6.5 (3.0)
- Known Exploited
- No
- Published
Vector: CVSS:3.0/AV:L/AC:L/PR:L/UI:N/S:C/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.
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:3.0/AV:L/AC:L/PR:L/UI:N/S:C/C:H/I:N/A:N24Primary CVE scoreVulnerability scoring details
Base CVSS 3.0 score
6.5MediumVector: CVSS:3.0/AV:L/AC:L/PR:L/UI:N/S:C/C:H/I:N/A:N
Source materials
- CVE List V5 sourceCVE List V5
- https://talosintelligence.com/vulnerability_reports/TALOS-2021-1255CVE 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.
Exposed IOCTL with Insufficient Access Control
Exposed IOCTL with Insufficient Access Control represents a recurring weakness pattern that can create exploitable paths when design, validation, or implementation controls are missing.