Security readout for executives and security teams
Plain-English summary
xArrow SCADA 7.2 and prior has a cross-site scripting flaw in a historical alarm page parameter. An unauthenticated attacker may be able to make a user interact with crafted content, causing attacker-controlled script to run in that user’s browser. The available sources rate this as medium severity, not a confirmed emergency.
Executive priority
Handle as a moderate-priority SCADA web security issue. It does not have confirmed active exploitation in the provided sources, but affected systems should be identified promptly and remediated according to CISA or vendor guidance because operator-facing SCADA interfaces are sensitive assets.
Technical view
CVE-2021-33021 is CWE-79 in xhisalarm.htm, specifically the edate parameter, affecting xArrow SCADA versions 7.2 and prior. CVSS 3.1 is 6.1: network exploitable, low complexity, no privileges required, user interaction required, scope changed, low confidentiality and integrity impact, no availability impact.
Likely exposure
Organizations using xArrow SCADA 7.2 or earlier are potentially exposed, especially where the SCADA web interface is reachable by users or networks that could receive attacker-controlled links or content. The bundle does not identify affected CPEs or confirm broader product versions beyond 7.2 and prior.
Exploitation context
The bundle does not show CISA KEV listing or other evidence of active exploitation. Exploitation requires user interaction, which lowers urgency compared with unauthenticated server-side compromise, but SCADA context increases operational concern because trusted operator sessions may be targeted.
Researcher notes
The evidence supports XSS in the edate parameter of xhisalarm.htm with no privileges required and user interaction required. The source bundle does not provide a patch version, exploit details, CPEs, or active exploitation evidence, so validation should focus on version confirmation and reachable interface exposure.
Mitigation direction
- Confirm whether xArrow SCADA 7.2 or prior is deployed.
- Review the CISA advisory and vendor guidance for supported fixes or mitigations.
- Restrict access to the SCADA web interface to trusted networks and users.
- Treat exposure reduction as interim until vendor remediation is confirmed.
Validation and detection
- Inventory xArrow SCADA versions and identify any 7.2 or earlier systems.
- Check whether xhisalarm.htm is reachable from user workstations or broader networks.
- Review web logs for unusual requests involving the edate parameter.
- Confirm whether compensating access controls protect affected SCADA interfaces.
Public sources used
Generated from the cited source records. This long-tail analysis has not been individually reviewed by a named human.
Conservative CVE-to-ATT&CK context
These mappings and lookup hints may be relevant to the vulnerability behavior, CWE, affected product, or exposure path. Glexia-inferred context is not an official MITRE, ATT&CK, CWE, or CVE Program mapping.
ATT&CK lookup starting points
Use these exact CWE pages and searches to review the Glexia ATT&CK library from this CVE's weakness and description context.
CWE-79: User-session and phishing behavior lookup
Client-side and session-facing weaknesses should be reviewed alongside initial-access and user-execution behaviors. Open the exact CWE lookup page first, then review the ATT&CK searches from that MITRE weakness context. This is a Glexia lookup hint, not an official ATT&CK mapping.
Open ATT&CK lookupExecution behavior lookup
The CVE wording references code or command execution, so execution technique review may help defensive triage. This is a Glexia inferred lookup path, not an official MITRE, ATT&CK, or CVE Program mapping.
Open ATT&CK lookupCVE-2021-33021 mapping review
Open the CVE-to-ATT&CK bridge for reviewed, inferred, or future official mappings tied to this CVE.
Open ATT&CK lookup- Severity
- Medium
- CVSS
- 6.1 (3.1)
- Known Exploited
- No
- Published
Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N
CNA and ADP enrichment extracted from CVE v5
These fields come from the CVE record and ADP containers, not from Glexia's Take. They preserve time-varying source decisions such as CISA SSVC, KEV status, CVSS metrics, and provider references.
CVSS vector scores
1 official scoreWe collect every scored CVSS vector available in the official CNA and ADP containers. When more than one version is present, the table keeps the source vectors side by side instead of collapsing them into the highest score.
CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N2.82.7Primary CVE scoreVulnerability scoring details
Base CVSS 3.1 score
6.1MediumVector: CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N
Source materials
- CVE List V5 sourceCVE List V5
- https://www.cisa.gov/uscert/ics/advisories/icsa-21-229-03CVE reference · x_refsource_CONFIRM
Products and packages named in the record
CWE details
CWE links open Glexia weakness intelligence pages with official CWE context, developer remediation guidance, and related CVE mappings.
Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting')
Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting') represents a recurring weakness pattern that can create exploitable paths when design, validation, or implementation controls are missing.