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CVE-2021-26828

8.8, high Known exploited

OpenPLC ScadaBR Unrestricted Upload of File with Dangerous Type Vulnerability

NVD (opens in a new tab) CVE.org (opens in a new tab) CISA KEV catalogue (opens in a new tab)
CVSS
8.8, high high CVSS v3.1
EPSS, next 30 days
39% higher than 98.5% of scored CVEs
Exploitation
Confirmed in the wild
Published
11 Jun 20215 years ago

Known exploited

CISA added this to the Known Exploited Vulnerabilities Catalog on 3 Dec 2025. US federal agencies had to remediate by 24 Dec 2025, a deadline that has passed.

Required action. Apply mitigations per vendor instructions, follow applicable BOD 22-01 guidance for cloud services, or discontinue use of the product if mitigations are unavailable.

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.

Details

Vendor
OpenPLC and 2 more
Product
Scadabr
Weakness
CWE-434 (opens in a new tab)
Status
Analyzed
Updated
17 Jun 2026
Assigner
cve@mitre.org

CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H

References 5

Exploit code 3

Patches and fixes 1

Other references 1

The kind is read from NVD's tags where present and from the shape of the URL otherwise, so treat it as a hint.

Other OpenPLC CVEs

Every OpenPLC CVE we hold

Same vendor in what we hold, not a known link between the flaws.

  • CVE-2021-26829 OpenPLC ScadaBR Cross-site Scripting Vulnerability KEV EPSS 48% 5.4, medium

Beyond this page

Is CVE-2021-26828 in your network?

This page tells you how dangerous CVE-2021-26828 is out there. Whether it sits on one of your devices, only a scan of your own network can tell. That is what our systems do, every day, for the companies we protect.

CVE-2021-26828 is in the CISA catalogue of exploited vulnerabilities: attackers are already exploiting it.

  • EXYS7600 OCELOT

    Find it before attackers do

    Ocelot scans your network on a schedule and reports every vulnerability it finds by its CVE identifier, with its CVSS score and how many of your hosts are affected. A finding like CVE-2021-26828 comes with the devices to patch.

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  • EXYS7950 KONDRA

    Detect it if it's exploited

    Until the patch is applied, Kondra monitors your network, events and endpoints in real time. It keeps an inventory of the software installed on every endpoint, and its anomaly detection rules flag what an attacker does once inside.

    Learn more about EXYS7950 KONDRA
Check your exposure

Assembled from the NVD 2.0 API, the CISA Known Exploited Vulnerabilities Catalog and FIRST EPSS. Scores are as of our last collection on 17 Oct 2026, not the live upstream state.