OpenPLC ScadaBR Cross-site Scripting Vulnerability
OpenPLC · ScadaBR
OpenPLC ScadaBR (through 0.9.1 on Linux and through 1.12.4 on Windows) contains a stored cross-site scripting flaw in its system_settings.shtm page, where input is not properly neutralized before being rendered in web pages. An attacker with low-privilege authenticated access to the application can plant malicious script that executes in the browser of another user, which requires that user to interact with the affected page.
OpenPLC ScadaBR through 0.9.1 on Linux and through 1.12.4 on Windows allows stored XSS via system_settings.shtm.
- Exploited
- Yes, in CISA KEV
- Reports
- 0
- Tactics
- 1/15
How an attack unfolds
Based on MITRE ATT&CKA public catalogue of the techniques attackers use, maintained by MITRE. Patchfirst uses it to describe what attackers do with a vulnerability. mappings. Select a step to see the evidence.What they do
Exploitation timelineDated milestones for a CVE: when it was disclosed, when exploit code became public, when exploitation was confirmed, and when threat reports named it.
First seen exploited 4 years after disclosure.
- Disclosedday 0
- First seen exploitedVulnCheck KEV evidence+4 yrs
- Added to CISA KEVEU database agrees+4 yrs
CISA KEV listing is when exploitation was confirmed, not necessarily the first attack.
MITRE ATT&CKA public catalogue of the techniques attackers use, maintained by MITRE. Patchfirst uses it to describe what attackers do with a vulnerability. techniques
1 TechniqueOne specific attacker behaviour in MITRE ATT&CK, such as T1190 “Exploit Public-Facing Application”. IDs with a dot, like T1059.004, are sub-techniques., grouped by TacticThe attacker’s goal at a stage of an attack in MITRE ATT&CK, such as Initial Access or Persistence. Each technique belongs to one or more tactics. in kill-chain order, 2 cited passages 1ExecutionTA0002
Stored XSS yields JavaScript execution in browser
allows stored XSS via system_settings.shtm
Lower-confidence links (1)
These come from early or generic mappings, text matching, or contradict this CVE’s details (for example a public-facing technique on a bug that needs a user to open a file). Shown for completeness.
- Exploit Public-Facing ApplicationT1190 needs user interaction; not a public-facing exploit
Detection
0 rules for this CVE · 29 general rules for its techniquesRules for this CVE
0Sigma ruleAn open, vendor-neutral detection rule for log data. Security teams convert Sigma rules into searches for their own SIEM. that reference CVE-2021-26829 directly.CVE-specific rules are not available in this build. Search SigmaHQ ↗
General rules for this CVE’s techniques
These detect the technique in general, not this specific vulnerability.
JavaScriptT1059.00729 general rules
- Adwind RAT / JRAThightest
- Adwind RAT / JRAT File Artifacthightest
- Csc.EXE Execution Form Potentially Suspicious Parenthightest
- Cscript/Wscript Uncommon Script Extension Executionhightest
- HackTool - CACTUSTORCH Remote Thread Creationhightest
- HackTool - Koadic Executionhightest
- HTML Help HH.EXE Suspicious Child Processhightest
- JXA In-memory Execution Via OSAScripthightest
Sigma rules © SigmaHQ, Detection Rule License 1.1; linked, not reproduced.
What security researchers reported
Not named in any threat report yetAlso mentioned in 50 community threat pulses (AlienVault OTX)
Weaker evidencePulses are indicator collections that anyone can publish. A mention is not confirmation of exploitation.
- Actively_Exploited_Kev | Oct 29, 202628 Oct 2026
- Actively_Exploited_Kev | Oct 28, 202627 Oct 2026
- Actively_Exploited_Kev | Oct 27, 202626 Oct 2026
- Actively_Exploited_Kev | Oct 24, 202623 Oct 2026
- Actively_Exploited_Kev | Oct 23, 202622 Oct 2026
- Actively_Exploited_Kev | Oct 22, 202621 Oct 2026
- 44 more on OTX