Security readout for executives and security teams
Plain-English summary
This flaw lets a low-privileged local attacker abuse PerFact OpenVPN-Client to make its backend start a new OpenVPN instance with attacker-controlled configuration. If successful, the attacker may execute code as SYSTEM, turning limited workstation access into full host compromise.
Executive priority
Treat this as high priority where PerFact OpenVPN-Client supports remote access or sensitive operations. It is not described as remotely exploitable from the internet alone, but it can turn limited local access into full system control.
Technical view
CVE-2021-27406 affects PerFact OpenVPN-Client 1.4.1.0 and prior. The issue is CWE-15: external control of system or configuration settings. The CVSS 3.1 score is 8.8. The bundle describes local-host applications sending a config command that causes privileged backend behavior.
Likely exposure
Exposure is limited to systems running PerFact OpenVPN-Client 1.4.1.0 or earlier. Risk is higher on workstations or remote-access hosts where untrusted users or applications can run locally.
Exploitation context
The source bundle does not show CISA KEV listing or other cited evidence of active exploitation. The described attacker already needs some local application execution or low-privileged access before attempting privilege escalation.
Researcher notes
Evidence in the bundle is sparse beyond the CVE description, CVSS vector, CWE-15, affected version ceiling, and CISA advisory reference. Avoid assuming exploit availability or a specific patch unless confirmed in vendor or CISA guidance.
Mitigation direction
- Inventory PerFact OpenVPN-Client installations and versions.
- Check CISA and PerFact guidance for a fixed release or vendor mitigation.
- Remove the client where it is not operationally required.
- Restrict untrusted local application execution on affected hosts.
- Prioritize hosts used for remote access or operational environments.
Validation and detection
- Confirm whether PerFact OpenVPN-Client is installed on managed endpoints.
- Verify no deployed instance is version 1.4.1.0 or earlier.
- Review endpoint telemetry for unexpected privileged OpenVPN process launches.
- Check whether vulnerable hosts allow non-admin users to run local applications.
- Document compensating controls where immediate remediation is unavailable.
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-15: 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-2021-27406 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
- 8.8 (3.1)
- Known Exploited
- No
- Published
Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
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:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H2.85.9Primary CVE scoreVulnerability scoring details
Base CVSS 3.1 score
8.8HighVector: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
Source materials
- CVE List V5 sourceCVE List V5
- https://www.cisa.gov/uscert/ics/advisories/icsa-21-056-01CVE reference
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.
External Control of System or Configuration Setting
External Control of System or Configuration Setting represents a recurring weakness pattern that can create exploitable paths when design, validation, or implementation controls are missing.