01 Record

CVE-2021-26829

OpenPLC ScadaBR through 0.9.1 on Linux and through 1.12.4 on Windows allows stored XSS via system_settings.shtm.

MediumKEVPUBLISHEDCNA: mitre

CNA base score5.4 CVSS v3.xCVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:L/I:L/A:N

View raw JSON

02 Description

OpenPLC ScadaBR through 0.9.1 on Linux and through 1.12.4 on Windows allows stored XSS via system_settings.shtm.

03 Exploitation and scoring

Exploitation

Exploited in the wild. Listed in the CISA Known Exploited Vulnerabilities catalog on 2025-11-28. Federal remediation due 2025-12-19.

SSVC decision

ExploitationactiveCISA reports credible evidence of active exploitation.
AutomatablenoAt least one step from reconnaissance to exploitation cannot be reliably automated.
Technical ImpactpartialSuccessful exploitation gives limited control of the vulnerable component.

CISA publishes the decision points, not a final SSVC decision. The decision also depends on mission and well-being impact, which is a property of your deployment rather than of the vulnerability.

EPSS probability

48.05% probability of exploitation activity in the next 30 days.

EPSS percentile

Equal to or higher than the score of 98.7% of scored records. A rank, not a probability.

NVD base score

5.4 (CVSS v3.x), scored by the NVD independently of the CNA.

NVD CVSS vector

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

NVD analysis status

Analyzed. NVD last modified this record on 2026-06-17.

Red Hat severity

No Red Hat rating. Red Hat rates the CVEs that affect its products.

Exploit-prediction scores from FIRST. Independent scoring and analysis status from the NVD. Vendor severity from Red Hat. Exploitation assessment and catalog membership from CISA.

04 Metadata

Published

2021-06-11 11:05Z5 YR AGO

Last updated

2025-12-02 04:56Z11 MO AGO

Reserved

2021-02-05

Assigning CNA

mitre

Record state

PUBLISHED

Severity

Medium (CVSS 5.4)

CNA CVSS vector

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

Weaknesses

CWE-79Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting')Base

Data version

5.2

Document digest

0d87a44e8ae660ae9b711b083f72453adbfc9ed7a06d7c54b1bd05d2e8242225

05 Affected products

VendorProductVersionsPlatforms

linuxlinux_kernelNot specified—

microsoftwindowsNot specified—

scadabrscadabrNot specified—

06 References

youtu.behttps://youtu.be/Xh6LPCiLMa8x_refsource_MISC
forum.scadabr.com.brhttp://forum.scadabr.com.br/t/report-falhas-de-seguranca-em-versoes-do-scadabr/3615/4x_refsource_MISC
www.forescout.comhttps://www.forescout.com/blog/anatomy-of-a-hacktivist-attack-russian-aligned-group-targets-otics/third-party-advisory
www.cisa.govhttps://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2021-26829government-resource