Security readout for executives and security teams
Plain-English summary
Vangene deltaFlow E-platform version 4 has a critical upload weakness. An unauthenticated remote attacker could upload and execute arbitrary files, potentially compromising the application, stored data, and server availability. Treat exposed instances as urgent until exposure and vendor guidance are confirmed.
Executive priority
Prioritize this as an urgent exposure-reduction item for any deltaFlow E-platform v4 deployment. The business risk is server compromise without login, but the provided evidence does not confirm active exploitation or a named patch.
Technical view
CVE-2021-28173 is a CWE-434 arbitrary file upload issue in deltaFlow E-platform v4. The upload function lacks proper access control, allowing remote, unauthenticated file upload and execution. CVSS 3.1 is 9.8, with network access, low complexity, and no user interaction required.
Likely exposure
Exposure is likely limited to organizations running Vangene deltaFlow E-platform version 4, especially if reachable from the internet or untrusted networks. The provided sources do not list other versions, hosted variants, or CPE identifiers.
Exploitation context
The sources describe unauthenticated remote upload and execution capability. The CVE is not listed as CISA KEV in the supplied bundle, and no provided source confirms active exploitation. The issue is still high impact because successful abuse could lead to full application compromise.
Researcher notes
The record is concise but clear: unauthenticated remote arbitrary file upload leading to execution in Vangene deltaFlow E-platform v4. Sources do not provide exploit details, affected subcomponents, fixed version, or detection indicators. Validate exposure and obtain vendor-specific remediation before closing risk.
Mitigation direction
- Check Vangene, TWCERT, and CHT Security guidance for fixed versions or official workarounds.
- Remove public internet access to affected deltaFlow E-platform instances where possible.
- Restrict upload endpoints to trusted networks and authenticated users using external controls.
- Review servers for unexpected uploaded files, new scripts, and suspicious webroot changes.
- Prioritize backup validation and recovery readiness for affected environments.
Validation and detection
- Inventory all deltaFlow E-platform deployments and confirm whether version 4 is present.
- Confirm whether affected upload functionality is reachable from untrusted networks.
- Review application and web server logs for unauthenticated upload activity.
- Inspect upload directories and executable paths for unexpected files.
- Document findings without running exploit attempts in production.
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-434: File access and web shell behavior lookup
File traversal and upload weaknesses can lead teams to review file, web shell, execution, and collection telemetry. 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 lookupFile access behavior lookup
The CVE wording references file access or upload behavior, so file telemetry and web shell review may help. This is a Glexia inferred lookup path, not an official MITRE, ATT&CK, or CVE Program mapping.
Open ATT&CK lookupCVE-2021-28173 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
- Critical
- CVSS
- 9.8 (3.1)
- Known Exploited
- No
- Published
Vector: CVSS:3.1/AV:N/AC:L/PR:N/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:N/UI:N/S:U/C:H/I:H/A:H3.95.9Primary CVE scoreVulnerability scoring details
Base CVSS 3.1 score
9.8CriticalVector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
Source materials
- CVE List V5 sourceCVE List V5
- https://www.chtsecurity.com/news/7f0874b5-516b-4637-842d-b6fb6c335c66CVE reference · x_refsource_MISC
- https://www.twcert.org.tw/tw/cp-132-4620-58f9c-1.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.
Unrestricted Upload of File with Dangerous Type
Unrestricted Upload of File with Dangerous Type represents a recurring weakness pattern that can create exploitable paths when design, validation, or implementation controls are missing.