CVE-2021-26828: OpenPLC ScadaBR Unrestricted Upload of File with Dangerous Type Vulnerability
- Is it exploited?
Yes. CISA added it to the Known Exploited Vulnerabilities catalog on 3 Dec 2025, 1,636 days after the CVE record was published.
- How likely is exploitation in the next 30 days?
- 39.1%
EPSS score, percentile 98.6 of all scored records
- How severe?
- 8.8 High
CVSS v3.1 base score, from CISA's enrichment of the record
- What should I do?
CISA deadline 24 Dec 2025. Apply mitigations per vendor instructions, follow applicable BOD 22-01 guidance for cloud services, or discontinue use of the product if mitigations are unavailable.
The CVE record links no vendor advisory, patch or mitigation.
- Which versions are affected?
Not stated. The CVE record gives vendor and product as “n/a” and the version as “unspecified”.
Source: CISA Known Exploited Vulnerabilities (KEV) catalog, 2026.10.28, as of 28 Oct 2026; FIRST Exploit Prediction Scoring System (EPSS), v2026.06.15, as of 28 Oct 2026; CVE List V5 (CVE Program), cve_2026-10-28_0000Z, as of 28 Oct 2026. About the data.
What to do
Required action, set by CISA
Apply mitigations per vendor instructions, follow applicable BOD 22-01 guidance for cloud services, or discontinue use of the product if mitigations are unavailable.
CISA due date for this action: 24 December 2025.
Advisories and patches
The CVE record links no vendor advisory, patch or mitigation.
Linked from CISA's catalog entry
Affected products and versions
The CVE record does not name affected products or versions: vendor and product are “n/a” and the version is “unspecified”.
Source: CVE List V5 (CVE Program), cve_2026-10-28_0000Z, as of 28 Oct 2026. About the data.
About this vulnerability
OpenPLC ScadaBR contains an unrestricted upload of file with dangerous type vulnerability that allows remote authenticated users to upload and execute arbitrary JSP files via view_edit.shtm.
Summary: CISA's KEV catalog, as of 28 Oct 2026.
- CISA added CVE-2021-26828 to its Known Exploited Vulnerabilities (KEV) catalog on 3 Dec 2025.
- CISA's ransomware flag for this entry is "Unknown": no evidence of ransomware use in the catalog, which is not proof of none.
- The due date CISA sets for the required action is 24 Dec 2025.
- The CVE record was published on 11 Jun 2021, 1,636 days before it was added to KEV.
- The CVE record carries a CVSS v3.1 base score of 8.8 (High), taken from CISA's enrichment of the record.
- FIRST's EPSS model puts the probability of exploitation in the next 30 days at 39.1% (percentile 98.6), as of 28 Oct 2026.
- CISA's SSVC assessment in the CVE record: exploitation active, automatable no, technical impact total.
Source: CISA Known Exploited Vulnerabilities (KEV) catalog, 2026.10.28, as of 28 Oct 2026; CVE List V5 (CVE Program), cve_2026-10-28_0000Z, as of 28 Oct 2026; FIRST Exploit Prediction Scoring System (EPSS), v2026.06.15, as of 28 Oct 2026. About the data.
Description
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.
Source: CVE List V5 (CVE Program), cve_2026-10-28_0000Z, as of 28 Oct 2026. About the data.
Weakness
- CWE-434: Unrestricted Upload of File with Dangerous Type
CWE and CAPEC are maintained by MITRE; the entries are those named in the CVE record and the KEV entry.
Timeline
| Date | Event |
|---|---|
| 11 Jun 2021 | CVE record published |
| 3 Dec 2025 | Added to CISA KEV |
| 4 Dec 2025 | CVE record last updated |
| 24 Dec 2025 | CISA due date for the required action |
References
More exploited OpenPLC vulnerabilities
- CVE-2021-26829: OpenPLC ScadaBR Cross-site Scripting Vulnerability