CVE-2021-26829
Confirmed PUBLISHEDOpenPLC ScadaBR through 0.9.1 on Linux and through 1.12.4 on Windows allows stored XSS via system_settings.shtm.
1 day faster than CISA KEV
Recommended Action
Prioritize remediation. Validate affected assets and apply vendor fixes on an accelerated timeline.
At a Glance
OpenPLC ScadaBR through 0.9.1 on Linux and through 1.12.4 on Windows allows stored XSS via system_settings.shtm.
- CVE Published
- Jun 11, 2021
- Exploitation Reported
- Jun 01, 2026
- CVSS
- 5.4 Medium
- EPSS
- 48.1%
Affected Versions
| Vendor | Product | Version | Status |
|---|---|---|---|
| n/a |
n/a
|
n/a |
Affected |
CVE References
- youtu.be/Xh6LPCiLMa8 youtu.be · CVE Record https://youtu.be/Xh6LPCiLMa8
- forum.scadabr.com.br/t/report-falhas-de-seguranca-em-versoes-do-s... forum.scadabr.com.br · CVE Record http://forum.scadabr.com.br/t/report-falhas-de-seguranca-em-versoes-d...
Recommended Actions
- Prioritize remediation. Validate affected assets and apply vendor fixes on an accelerated timeline.
- Use the Pro API to automate enrichment, telemetry, and workflow delivery for VM, SOC, and CTI pipelines.
Known Exploited Vulnerability Sources
Catalogues that list this CVE as a known exploited vulnerability.
Per-source evidence links for KEV attestations are available through the KEVIntel Pro API.
Learn about Pro API access| Source | Added |
|---|---|
| CVE First | 2026-06-01 10:45 UTC |
| CISA | 2026-06-02 14:04 UTC |
No detection artifacts or sensor request patterns are available for this CVE yet.
Check back as sensor telemetry and scanner integrations are updated.
Virtual Patch
Compensating WAF rules to help reduce exposure to this CVE. Rule content and deployable vendor exports are available with KEVIntel Enterprise.
KEVIntel does not currently have a virtual patch for this CVE. When available, KEVIntel virtual patches ship as deployable ModSecurity, Cloudflare, and AWS WAF rules.
Enterprise feature. Virtual patch rule content and deployable vendor exports (ModSecurity, Cloudflare, AWS WAF) are available to KEVIntel Enterprise users.
CVSS Scores
CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:L/I:L/A:N
AV:N/AC:M/Au:S/C:N/I:P/A:N
Exploitation Status
Exploited in the wild
Recorded 2026-06-01 10:45:14 UTC · CVE
Weaknesses (CWE)
-
Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting')
Timeline
Key exploitation, disclosure, scanner coverage, and KEV attestation events for this CVE.
-
14:04 UTC about 2 months ago14:04 UTC · about 2 months ago
Added to CISA KEV
Listed in the CISA Known Exploited Vulnerabilities catalog
-
10:45 UTC about 2 months ago10:45 UTC · about 2 months ago
Added to KEVIntel KEV Feed
High-confidence, third-party attested exploitation
-
11:05 UTC about 5 years ago11:05 UTC · about 5 years ago
CVE published
Vulnerability disclosed publicly
-
00:00 UTC over 5 years ago00:00 UTC · over 5 years ago
CVE ID reserved
Identifier reserved by the CNA
Automate This Intelligence with the Pro API
Confidence scoring, exploit status, sensor telemetry, PoCs, scanner integrations, mentions, and tags are available programmatically for VM, SOC, and CTI workflows.
Pro API Example
GET /api/v2/pro/kevs/CVE-2021-26829
{
"cve_id": "CVE-2021-26829",
"title": "OpenPLC ScadaBR through 0.9.1 on Linux and through 1.12.4 on Windows allows s...",
"affected_vendor": "OpenPLC",
"affected_product": "ScadaBR",
"affected_versions": [
{ "vendor": "...", "product": "...", "status": "affected", "display_label": "..." }
],
"confidence": "Confirmed",
"cvss_score": 5.4,
"epss_score": 0.4805,
"exploit_status": {
"exploited_in_the_wild": true,
"active_exploitation_observed": false
},
"sensor_telemetry": { "...": "Pro API fields" },
"proof_of_concepts": [ "..." ],
"scanner_integrations": [ "..." ]
}