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ExploitedIn CISA KEVFix available

CVE-2021-26828

Exploitation confirmed. First attested on 2025-12-03 by CISA-ADP, CISA KEV, GCVE · kevintel.

  • Published2021-06-11
  • WeaknessCWE-434

Am I affected?

With a domain, we read the version its public headers and pages expose. A distribution build can carry the fix under an older number.

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.

Timeline

dates in UTC
  1. 2021-06-1112:15CVE publishedNVD
  2. 2025-12-03Added to the CISA KEV catalogCISA KEV
  3. 2025-12-03Listed as exploited by GCVEGCVE
  4. 2025-12-03Exploitation first reportedCISA KEV
  5. 2025-12-0318:04SSVC exploitation set to activeCISA-ADP

Observed activity

isMalicious corpus · updated 2026-11-03 21:37 UTC
Indicators tagged with this CVE, per day0 indicators over 7 days
Block these indicators
  • Firewall list (EDL, text): https://api.ismalicious.com/edl/cve/CVE-2021-26828?format=txt
  • CSV export: https://api.ismalicious.com/edl/cve/CVE-2021-26828?format=csv
  • TAXII collection of exploited CVEs
  • The EDL and CSV take an API key on the Pro plan.

Versions per branch

NVD
Scadabrversion to verify
BranchAffectedFixed in
0.9≤ 0.9.1no fix published
1.12≤ 1.12.4no fix published

as publishedRanges as NVD and OSV publish them; a distribution’s build can be fixed under an older number.

Fix

  1. CISA’s 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.due 2025-12-24

Advisories and patches

Detection

read 2026-11-02 22:42 UTC
Nuclei template
none so far
ProjectDiscovery
Exploit-DB
no entry
Exploit-DB
Proof-of-concept repositories
3 repositories, unverifiedhev0x/CVE-2021-26828_ScadaBR_RCEridpath/CVE-2021-26828-Ultimateh002733/CVE-2021-26828
PoC-in-GitHub
Metasploit modules
none listed
Metasploit Framework

CISA Known Exploited Vulnerability

Date Added
2025-12-03
Patch Due Date
2025-12-24
Ransomware Use
Unknown
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.

Sources

Identifiers

Technical details

CVSS v3 Vector
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
Published
2021-06-11
Last Modified
2026-06-17
NVD status
Analyzed
GitHub Advisory
GHSA-j87g-5g8x-jjxc

Frequently asked questions

What is CVE-2021-26828?

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.

Is CVE-2021-26828 actively exploited?

Yes. CVE-2021-26828 is on the CISA Known Exploited Vulnerabilities (KEV) catalog, meaning it has been confirmed as actively exploited in the wild. CISA requires federal agencies to patch by 2025-12-24.

What is the CVSS score for CVE-2021-26828?

CVE-2021-26828 has a CVSS v3 base score of 8.8 (HIGH severity), with vector string CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H.

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Sources for this record