CVE-2021-26829 (GCVE-0-2021-26829)
Vulnerability from cvelistv5 – Published: 2021-06-11 11:05 – Updated: 2025-12-02 04:56- n/a
- CWE-79 - Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting')
| URL | Tags |
|---|---|
| https://youtu.be/Xh6LPCiLMa8 | x_refsource_MISC |
| http://forum.scadabr.com.br/t/report-falhas-de-se… | x_refsource_MISC |
| https://www.forescout.com/blog/anatomy-of-a-hackt… | third-party-advisory |
| https://www.cisa.gov/known-exploited-vulnerabilit… | government-resource |
CISA
Known Exploited Vulnerability - GCVE BCP-07 Compliant
Exploited: Yes
Timestamps
Scope
Evidence
Type: Vendor Report
Signal: Successful Exploitation
Confidence: 80%
Source: cisa-kev
Details
| Cwes | CWE-79 |
|---|---|
| Feed | CISA Known Exploited Vulnerabilities Catalog |
| Product | ScadaBR |
| Due Date | 2025-12-19 |
| Date Added | 2025-11-28 |
| Vendorproject | OpenPLC |
| Vulnerabilityname | OpenPLC ScadaBR Cross-site Scripting Vulnerability |
| Knownransomwarecampaignuse | Unknown |
References
Previdian
Known Exploited Vulnerability - GCVE BCP-07 Compliant
Exploited: Yes
Timestamps
Scope
Evidence
Type: Public Report
Signal: Successful Exploitation
Confidence: 70%
Source: kevintel
Details
| Feed | KEVIntel (kevintel.com) |
|---|---|
| Title | OpenPLC ScadaBR through 0.9.1 on Linux and through 1.12.4 on Windows allows stored XSS via system_settings.shtm. |
| Vendor | OpenPLC |
| Product | ScadaBR |
| Added Date | 2026-06-01T10:45:14.727Z |
| Cvss Score | 5.4 |
| Epss Score | 0.4805 |
| Cvss Severity | MEDIUM |
| Epss Percentile | 0.98709 |
| Used In Malware | unknown |
| Ahead Of Cisa Kev |
|
| Not Yet In Cisa Kev | False |
References
{
"containers": {
"adp": [
{
"providerMetadata": {
"dateUpdated": "2024-08-03T20:33:41.158Z",
"orgId": "af854a3a-2127-422b-91ae-364da2661108",
"shortName": "CVE"
},
"references": [
{
"tags": [
"x_refsource_MISC",
"x_transferred"
],
"url": "https://youtu.be/Xh6LPCiLMa8"
},
{
"tags": [
"x_refsource_MISC",
"x_transferred"
],
"url": "http://forum.scadabr.com.br/t/report-falhas-de-seguranca-em-versoes-do-scadabr/3615/4"
}
],
"title": "CVE Program Container"
},
{
"metrics": [
{
"cvssV3_1": {
"attackComplexity": "LOW",
"attackVector": "NETWORK",
"availabilityImpact": "NONE",
"baseScore": 5.4,
"baseSeverity": "MEDIUM",
"confidentialityImpact": "LOW",
"integrityImpact": "LOW",
"privilegesRequired": "LOW",
"scope": "CHANGED",
"userInteraction": "REQUIRED",
"vectorString": "CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:L/I:L/A:N",
"version": "3.1"
}
},
{
"other": {
"content": {
"id": "CVE-2021-26829",
"options": [
{
"Exploitation": "active"
},
{
"Automatable": "no"
},
{
"Technical Impact": "partial"
}
],
"role": "CISA Coordinator",
"timestamp": "2025-12-01T00:00:00+00:00",
"version": "2.0.3"
},
"type": "ssvc"
}
},
{
"other": {
"content": {
"dateAdded": "2025-11-28",
"reference": "https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2021-26829"
},
"type": "kev"
}
}
],
"problemTypes": [
{
"descriptions": [
{
"cweId": "CWE-79",
"description": "CWE-79 Improper Neutralization of Input During Web Page Generation (\u0027Cross-site Scripting\u0027)",
"lang": "en",
"type": "CWE"
}
]
}
],
"providerMetadata": {
"dateUpdated": "2025-12-02T04:56:04.472Z",
"orgId": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
"shortName": "CISA-ADP"
},
"references": [
{
"tags": [
"third-party-advisory"
],
"url": "https://www.forescout.com/blog/anatomy-of-a-hacktivist-attack-russian-aligned-group-targets-otics/"
},
{
"tags": [
"government-resource"
],
"url": "https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2021-26829"
}
],
"timeline": [
{
"lang": "en",
"time": "2025-11-28T00:00:00.000Z",
"value": "CVE-2021-26829 added to CISA KEV"
}
],
"title": "CISA ADP Vulnrichment"
}
],
"cna": {
"affected": [
{
"product": "n/a",
"vendor": "n/a",
"versions": [
{
"status": "affected",
"version": "n/a"
}
]
}
],
"descriptions": [
{
"lang": "en",
"value": "OpenPLC ScadaBR through 0.9.1 on Linux and through 1.12.4 on Windows allows stored XSS via system_settings.shtm."
}
],
"problemTypes": [
{
"descriptions": [
{
"description": "n/a",
"lang": "en",
"type": "text"
}
]
}
],
"providerMetadata": {
"dateUpdated": "2021-06-11T11:05:23.000Z",
"orgId": "8254265b-2729-46b6-b9e3-3dfca2d5bfca",
"shortName": "mitre"
},
"references": [
{
"tags": [
"x_refsource_MISC"
],
"url": "https://youtu.be/Xh6LPCiLMa8"
},
{
"tags": [
"x_refsource_MISC"
],
"url": "http://forum.scadabr.com.br/t/report-falhas-de-seguranca-em-versoes-do-scadabr/3615/4"
}
],
"x_legacyV4Record": {
"CVE_data_meta": {
"ASSIGNER": "cve@mitre.org",
"ID": "CVE-2021-26829",
"STATE": "PUBLIC"
},
"affects": {
"vendor": {
"vendor_data": [
{
"product": {
"product_data": [
{
"product_name": "n/a",
"version": {
"version_data": [
{
"version_value": "n/a"
}
]
}
}
]
},
"vendor_name": "n/a"
}
]
}
},
"data_format": "MITRE",
"data_type": "CVE",
"data_version": "4.0",
"description": {
"description_data": [
{
"lang": "eng",
"value": "OpenPLC ScadaBR through 0.9.1 on Linux and through 1.12.4 on Windows allows stored XSS via system_settings.shtm."
}
]
},
"problemtype": {
"problemtype_data": [
{
"description": [
{
"lang": "eng",
"value": "n/a"
}
]
}
]
},
"references": {
"reference_data": [
{
"name": "https://youtu.be/Xh6LPCiLMa8",
"refsource": "MISC",
"url": "https://youtu.be/Xh6LPCiLMa8"
},
{
"name": "http://forum.scadabr.com.br/t/report-falhas-de-seguranca-em-versoes-do-scadabr/3615/4",
"refsource": "MISC",
"url": "http://forum.scadabr.com.br/t/report-falhas-de-seguranca-em-versoes-do-scadabr/3615/4"
}
]
}
}
}
},
"cveMetadata": {
"assignerOrgId": "8254265b-2729-46b6-b9e3-3dfca2d5bfca",
"assignerShortName": "mitre",
"cveId": "CVE-2021-26829",
"datePublished": "2021-06-11T11:05:23.000Z",
"dateReserved": "2021-02-05T00:00:00.000Z",
"dateUpdated": "2025-12-02T04:56:04.472Z",
"state": "PUBLISHED"
},
"dataType": "CVE_RECORD",
"dataVersion": "5.2",
"vulnerability-lookup:meta": {
"cisa_known_exploited": {
"cveID": "CVE-2021-26829",
"cwes": [
"CWE-79"
],
"dateAdded": "2025-11-28",
"dueDate": "2025-12-19",
"forensicTriage": "No",
"knownRansomwareCampaignUse": "Unknown",
"notes": "This vulnerability could affect an open-source component, third-party library, protocol, or proprietary implementation that could be used by different products. For more information, please see: https://github.com/SCADA-LTS/Scada-LTS/pull/3211 ; https://nvd.nist.gov/vuln/detail/CVE-2021-26829",
"product": "ScadaBR",
"requiredAction": "Apply mitigations per vendor instructions, follow applicable BOD 22-01 guidance for cloud services, or discontinue use of the product if mitigations are unavailable.",
"shortDescription": "OpenPLC ScadaBR contains a cross-site scripting vulnerability via system_settings.shtm.",
"vendorProject": "OpenPLC",
"vulnerabilityName": "OpenPLC ScadaBR Cross-site Scripting Vulnerability"
},
"epss": {
"cve": "CVE-2021-26829",
"date": "2026-09-20",
"epss": "0.4805",
"percentile": "0.988"
},
"nvd": {
"cve": {
"cisaActionDue": "2025-12-19",
"cisaExploitAdd": "2025-11-28",
"cisaRequiredAction": "Apply mitigations per vendor instructions, follow applicable BOD 22-01 guidance for cloud services, or discontinue use of the product if mitigations are unavailable.",
"cisaVulnerabilityName": "OpenPLC ScadaBR Cross-site Scripting Vulnerability",
"configurations": [
{
"nodes": [
{
"cpeMatch": [
{
"criteria": "cpe:2.3:a:scadabr:scadabr:*:*:*:*:*:*:*:*",
"matchCriteriaId": "DE4BEBE0-2A0C-4B10-8E00-732DA4BDD6BB",
"versionEndIncluding": "0.9.1",
"vulnerable": true
}
],
"negate": false,
"operator": "OR"
},
{
"cpeMatch": [
{
"criteria": "cpe:2.3:o:linux:linux_kernel:-:*:*:*:*:*:*:*",
"matchCriteriaId": "703AF700-7A70-47E2-BC3A-7FD03B3CA9C1",
"vulnerable": false
}
],
"negate": false,
"operator": "OR"
}
],
"operator": "AND"
},
{
"nodes": [
{
"cpeMatch": [
{
"criteria": "cpe:2.3:a:scadabr:scadabr:*:*:*:*:*:*:*:*",
"matchCriteriaId": "EDADC64F-C764-48A3-8AF4-CE3AF50B6F1F",
"versionEndIncluding": "1.12.4",
"vulnerable": true
}
],
"negate": false,
"operator": "OR"
},
{
"cpeMatch": [
{
"criteria": "cpe:2.3:o:microsoft:windows:-:*:*:*:*:*:*:*",
"matchCriteriaId": "A2572D17-1DE6-457B-99CC-64AFD54487EA",
"vulnerable": false
}
],
"negate": false,
"operator": "OR"
}
],
"operator": "AND"
}
],
"cveTags": [],
"descriptions": [
{
"lang": "en",
"value": "OpenPLC ScadaBR through 0.9.1 on Linux and through 1.12.4 on Windows allows stored XSS via system_settings.shtm."
},
{
"lang": "es",
"value": "OpenPLC ScadaBR versiones hasta 0.9.1 en Linux y versiones hasta 1.12.4 en Windows, permite un ataque de tipo XSS almacenado por medio del archivo system_settings.shtm"
}
],
"id": "CVE-2021-26829",
"lastModified": "2025-12-01T15:23:18.697",
"metrics": {
"cvssMetricV2": [
{
"acInsufInfo": false,
"baseSeverity": "LOW",
"cvssData": {
"accessComplexity": "MEDIUM",
"accessVector": "NETWORK",
"authentication": "SINGLE",
"availabilityImpact": "NONE",
"baseScore": 3.5,
"confidentialityImpact": "NONE",
"integrityImpact": "PARTIAL",
"vectorString": "AV:N/AC:M/Au:S/C:N/I:P/A:N",
"version": "2.0"
},
"exploitabilityScore": 6.8,
"impactScore": 2.9,
"obtainAllPrivilege": false,
"obtainOtherPrivilege": false,
"obtainUserPrivilege": false,
"source": "nvd@nist.gov",
"type": "Primary",
"userInteractionRequired": true
}
],
"cvssMetricV31": [
{
"cvssData": {
"attackComplexity": "LOW",
"attackVector": "NETWORK",
"availabilityImpact": "NONE",
"baseScore": 5.4,
"baseSeverity": "MEDIUM",
"confidentialityImpact": "LOW",
"integrityImpact": "LOW",
"privilegesRequired": "LOW",
"scope": "CHANGED",
"userInteraction": "REQUIRED",
"vectorString": "CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:L/I:L/A:N",
"version": "3.1"
},
"exploitabilityScore": 2.3,
"impactScore": 2.7,
"source": "nvd@nist.gov",
"type": "Primary"
},
{
"cvssData": {
"attackComplexity": "LOW",
"attackVector": "NETWORK",
"availabilityImpact": "NONE",
"baseScore": 5.4,
"baseSeverity": "MEDIUM",
"confidentialityImpact": "LOW",
"integrityImpact": "LOW",
"privilegesRequired": "LOW",
"scope": "CHANGED",
"userInteraction": "REQUIRED",
"vectorString": "CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:L/I:L/A:N",
"version": "3.1"
},
"exploitabilityScore": 2.3,
"impactScore": 2.7,
"source": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
"type": "Secondary"
}
]
},
"published": "2021-06-11T12:15:12.053",
"references": [
{
"source": "cve@mitre.org",
"tags": [
"Vendor Advisory"
],
"url": "http://forum.scadabr.com.br/t/report-falhas-de-seguranca-em-versoes-do-scadabr/3615/4"
},
{
"source": "cve@mitre.org",
"tags": [
"Exploit",
"Third Party Advisory"
],
"url": "https://youtu.be/Xh6LPCiLMa8"
},
{
"source": "af854a3a-2127-422b-91ae-364da2661108",
"tags": [
"Vendor Advisory"
],
"url": "http://forum.scadabr.com.br/t/report-falhas-de-seguranca-em-versoes-do-scadabr/3615/4"
},
{
"source": "af854a3a-2127-422b-91ae-364da2661108",
"tags": [
"Exploit",
"Third Party Advisory"
],
"url": "https://youtu.be/Xh6LPCiLMa8"
},
{
"source": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
"tags": [
"US Government Resource"
],
"url": "https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2021-26829"
},
{
"source": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
"tags": [
"Third Party Advisory"
],
"url": "https://www.forescout.com/blog/anatomy-of-a-hacktivist-attack-russian-aligned-group-targets-otics/"
}
],
"sourceIdentifier": "cve@mitre.org",
"vulnStatus": "Analyzed",
"weaknesses": [
{
"description": [
{
"lang": "en",
"value": "CWE-79"
}
],
"source": "nvd@nist.gov",
"type": "Primary"
},
{
"description": [
{
"lang": "en",
"value": "CWE-79"
}
],
"source": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
"type": "Secondary"
}
]
}
},
"redhat_vex": {
"current_release_date": "2026-03-27T14:28:03+00:00",
"cve": "CVE-2021-26829",
"id": "CVE-2021-26829",
"initial_release_date": "2021-01-01T00:00:00+00:00",
"product_status:known_not_affected": "1",
"source": "Red Hat CSAF VEX",
"status": "final",
"title": "CVE-2021-26829",
"url": "https://security.access.redhat.com/data/csaf/v2/vex/2021/cve-2021-26829.json",
"version": "3"
},
"vulnrichment": {
"containers": {
"adp": [
{
"providerMetadata": {
"dateUpdated": "2024-08-03T20:33:41.158Z",
"orgId": "af854a3a-2127-422b-91ae-364da2661108",
"shortName": "CVE"
},
"references": [
{
"tags": [
"x_refsource_MISC",
"x_transferred"
],
"url": "https://youtu.be/Xh6LPCiLMa8"
},
{
"tags": [
"x_refsource_MISC",
"x_transferred"
],
"url": "http://forum.scadabr.com.br/t/report-falhas-de-seguranca-em-versoes-do-scadabr/3615/4"
}
],
"title": "CVE Program Container"
},
{
"metrics": [
{
"cvssV3_1": {
"attackComplexity": "LOW",
"attackVector": "NETWORK",
"availabilityImpact": "NONE",
"baseScore": 5.4,
"baseSeverity": "MEDIUM",
"confidentialityImpact": "LOW",
"integrityImpact": "LOW",
"privilegesRequired": "LOW",
"scope": "CHANGED",
"userInteraction": "REQUIRED",
"vectorString": "CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:L/I:L/A:N",
"version": "3.1"
}
},
{
"other": {
"content": {
"id": "CVE-2021-26829",
"options": [
{
"Exploitation": "active"
},
{
"Automatable": "no"
},
{
"Technical Impact": "partial"
}
],
"role": "CISA Coordinator",
"timestamp": "2025-11-28T18:31:38.297722Z",
"version": "2.0.3"
},
"type": "ssvc"
}
},
{
"other": {
"content": {
"dateAdded": "2025-11-28",
"reference": "https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2021-26829"
},
"type": "kev"
}
}
],
"problemTypes": [
{
"descriptions": [
{
"cweId": "CWE-79",
"description": "CWE-79 Improper Neutralization of Input During Web Page Generation (\u0027Cross-site Scripting\u0027)",
"lang": "en",
"type": "CWE"
}
]
}
],
"providerMetadata": {
"dateUpdated": "2025-11-27T16:09:49.230Z",
"orgId": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
"shortName": "CISA-ADP"
},
"references": [
{
"tags": [
"third-party-advisory"
],
"url": "https://www.forescout.com/blog/anatomy-of-a-hacktivist-attack-russian-aligned-group-targets-otics/"
},
{
"tags": [
"government-resource"
],
"url": "https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2021-26829"
}
],
"timeline": [
{
"lang": "en",
"time": "2025-11-28T00:00:00.000Z",
"value": "CVE-2021-26829 added to CISA KEV"
}
],
"title": "CISA ADP Vulnrichment"
}
],
"cna": {
"affected": [
{
"product": "n/a",
"vendor": "n/a",
"versions": [
{
"status": "affected",
"version": "n/a"
}
]
}
],
"descriptions": [
{
"lang": "en",
"value": "OpenPLC ScadaBR through 0.9.1 on Linux and through 1.12.4 on Windows allows stored XSS via system_settings.shtm."
}
],
"problemTypes": [
{
"descriptions": [
{
"description": "n/a",
"lang": "en",
"type": "text"
}
]
}
],
"providerMetadata": {
"dateUpdated": "2021-06-11T11:05:23.000Z",
"orgId": "8254265b-2729-46b6-b9e3-3dfca2d5bfca",
"shortName": "mitre"
},
"references": [
{
"tags": [
"x_refsource_MISC"
],
"url": "https://youtu.be/Xh6LPCiLMa8"
},
{
"tags": [
"x_refsource_MISC"
],
"url": "http://forum.scadabr.com.br/t/report-falhas-de-seguranca-em-versoes-do-scadabr/3615/4"
}
],
"x_legacyV4Record": {
"CVE_data_meta": {
"ASSIGNER": "cve@mitre.org",
"ID": "CVE-2021-26829",
"STATE": "PUBLIC"
},
"affects": {
"vendor": {
"vendor_data": [
{
"product": {
"product_data": [
{
"product_name": "n/a",
"version": {
"version_data": [
{
"version_value": "n/a"
}
]
}
}
]
},
"vendor_name": "n/a"
}
]
}
},
"data_format": "MITRE",
"data_type": "CVE",
"data_version": "4.0",
"description": {
"description_data": [
{
"lang": "eng",
"value": "OpenPLC ScadaBR through 0.9.1 on Linux and through 1.12.4 on Windows allows stored XSS via system_settings.shtm."
}
]
},
"problemtype": {
"problemtype_data": [
{
"description": [
{
"lang": "eng",
"value": "n/a"
}
]
}
]
},
"references": {
"reference_data": [
{
"name": "https://youtu.be/Xh6LPCiLMa8",
"refsource": "MISC",
"url": "https://youtu.be/Xh6LPCiLMa8"
},
{
"name": "http://forum.scadabr.com.br/t/report-falhas-de-seguranca-em-versoes-do-scadabr/3615/4",
"refsource": "MISC",
"url": "http://forum.scadabr.com.br/t/report-falhas-de-seguranca-em-versoes-do-scadabr/3615/4"
}
]
}
}
}
},
"cveMetadata": {
"assignerOrgId": "8254265b-2729-46b6-b9e3-3dfca2d5bfca",
"assignerShortName": "mitre",
"cveId": "CVE-2021-26829",
"datePublished": "2021-06-11T11:05:23.000Z",
"dateReserved": "2021-02-05T00:00:00.000Z",
"dateUpdated": "2025-12-02T04:56:04.472Z",
"state": "PUBLISHED"
},
"dataType": "CVE_RECORD",
"dataVersion": "5.2"
}
}
}
Sightings
| Author | Source | Type | Date | Other |
|---|
Nomenclature
- Seen: The vulnerability was mentioned, discussed, or observed by the user.
- Confirmed: The vulnerability has been validated from an analyst's perspective.
- Published Proof of Concept: A public proof of concept is available for this vulnerability.
- Exploited: The vulnerability was observed as exploited by the user who reported the sighting.
- Patched: The vulnerability was observed as successfully patched by the user who reported the sighting.
- Not exploited: The vulnerability was not observed as exploited by the user who reported the sighting.
- Not confirmed: The user expressed doubt about the validity of the vulnerability.
- Not patched: The vulnerability was not observed as successfully patched by the user who reported the sighting.
The approach is described in our paper Mapping CVEs to MITRE ATT&CK Techniques: A Curated Gold-Set Classifier and the Limits of LLM-Assisted Label Expansion.
Browse all ATT&CK techniques and the vulnerabilities related to each.
Related by attack behaviour
Vulnerabilities whose description is nearest to this one in the vector space of the CIRCL/vulnerability-attack-technique-biencoder model. This is a similarity search over the bi-encoder space (plain cosine), not a classification, and it has no measured accuracy.