CVE-2021-26828
Scadabr ≤ 0.9.1
Raw vector
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:HCVSS and EPSS are reproduced from their sources (NVD, FIRST EPSS). Risk Priority is our own derived reading, not an NVD score.
Summary
CVE-2021-26828 is a high-severity Unrestricted Upload of File with Dangerous Type (CWE-434) vulnerability in Scadabr Scadabr. Its CVSS base score is 8.8 (High).
Operationally, exploitation aligns with the MITRE ATT&CK technique Data Obfuscation (T1001); ranked in the top 1% of CVEs by exploit likelihood; CISA has added it to the Known Exploited Vulnerabilities catalog; a public proof-of-concept is referenced.
Deeper analysis AI-assisted summary
Synthesised by an AI model from the NVD description and linked references — a reading aid, not an authoritative source.
OpenPLC ScadaBR through version 0.9.1 on Linux and through 1.12.4 on Windows contains an unrestricted file upload vulnerability tracked as CVE-2021-26828 and assigned CWE-434. Remote authenticated users can upload arbitrary JSP files through the view_edit.shtm endpoint and subsequently execute them on the server.
An attacker with valid low-privileged credentials can exploit the flaw over the network without user interaction to achieve arbitrary code execution. Successful exploitation grants full control over confidentiality, integrity, and availability of the affected SCADA system, consistent with the CVSS 8.8 base score.
Public exploit code and proof-of-concept demonstrations have been published, including a shell-upload Metasploit module on Packet Storm and a detailed video walkthrough, confirming that working attacks against the listed versions are readily available. No official patch or mitigation guidance appears in the referenced advisories.
OWASP Top 10 for Web (2025)
EU & UK References
- 🇪🇺 ENISA EUVD: EUVD-2021-13613
Vulnerability Data
OpenPLC ScadaBR through 0.9.1 on Linux and through 1.12.4 on Windows allows remote authenticated users to upload and execute arbitrary JSP files via view_edit.shtm.
- CWE(s)
- KEV Date Added
- 03 December 2025
Related Threats
MITRE ATT&CK Enterprise Techniques
CVEs Like This One
Affected Assets
Mitigating Controls
Control response
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V5.1.1
Likely Mitigating Controls AI
Per-CVE control mapping for this CVE has not run yet; the list below is derived from the weakness types (CWEs) cited in the NVD entry.
Requiring identifiable owners for portable devices reduces the attack surface for unrestricted uploads of dangerous file types via anonymous media.
Dangerous file uploads can be detonated in the chamber to determine malice before any production write or execution occurs.
Prevents unrestricted writing of arbitrary or malicious firmware by keeping hardware write-protect enabled except under tightly controlled manual procedures.
Scans files from external sources on download/open/execute, blocking unrestricted uploads of dangerous file types.
Mitigating Controls (NIST CSF 2.0) AI
Derived directly from the weakness types (CWEs) cited in the NVD entry via our AI-authored CWE→CSF cross-walk (authority under review) — links open the control.
Hardened configuration baselines can enforce allowed file types and processing rules.
Restricting execution of unauthorized software directly blocks dangerous uploaded files from running.
Secure development practices include input validation and file-type restrictions that prevent this weakness.
Mitigating Controls (ISO/IEC 27001:2022 Annex A) AI
Derived directly from the weakness types (CWEs) cited in the NVD entry via our AI-authored CWE→ISO cross-walk (authority under review) — links open the control.