Security readout for executives and security teams
Plain-English summary
ABB's EIBPORT V3 KNX building-automation gateways have a web flaw that lets an attacker craft a malicious link which, when clicked by a logged-in operator, runs hostile script in their browser session. That can hijack the operator's access to the device and, by extension, the building controls it manages. ABB has released firmware 3.9.2 to fix it.
Executive priority
Schedule a planned firmware upgrade in the next maintenance window. This is not an emergency drop-everything patch, but the affected gateways control physical building systems, so leaving it unaddressed creates avoidable operational and safety risk.
Technical view
CVE-2021-22291 is a reflected cross-site scripting (CWE-79) flaw in ABB EIBPORT V3 KNX and EIBPORT V3 KNX GSM web interfaces prior to firmware 3.9.2. User-supplied input is reflected into a generated page without proper neutralization. Exploitation requires an authenticated user to interact with an attacker-supplied URL (CVSS 4.0 8.5, AV:N/AC:L/PR:L/UI:A), enabling session abuse against the building automation controller.
Likely exposure
EIBPORT V3 KNX and KNX GSM gateways running firmware below 3.9.2, particularly any units with web management reachable from operator workstations, jump hosts, or the internet. Building automation deployments that share browser sessions with general-purpose web use are most at risk.
Exploitation context
Not listed in CISA KEV and no public reports of in-the-wild exploitation are cited in the source bundle. Exploitation requires a privileged user to be tricked into loading a crafted URL, so phishing or watering-hole delivery is the practical attack path. Impact is bounded to the victim's authenticated session against the gateway.
Researcher notes
CVSS 4.0 8.5 reflects authenticated, user-interaction-required reflected XSS with high confidentiality, integrity, and availability impact on the vulnerable component. No CPEs, exploit PoC, or KEV entry are referenced; affected-version metadata in the CVE record is sparse (defaultStatus "unaffected" with versions "0"), so rely on the ABB advisory text "before 3.9.2" as the authoritative fixed version statement.
Mitigation direction
- Upgrade EIBPORT V3 KNX and KNX GSM firmware to 3.9.2 or later per ABB advisory.
- Restrict EIBPORT web management to a trusted management VLAN; block internet exposure.
- Require operators to use a dedicated browser profile when administering the gateway.
- Enforce least privilege and unique accounts on EIBPORT to limit session abuse impact.
- Train operators to avoid following untrusted links while authenticated to OT devices.
Validation and detection
- Inventory all EIBPORT V3 KNX and KNX GSM units and record installed firmware versions.
- Confirm post-upgrade build reports 3.9.2 or higher on each device.
- Review network ACLs and firewall rules to verify management UI is not internet-reachable.
- Check web server and authentication logs for unusual session activity from operator accounts.
- Validate ABB advisory 9AKK108471A7808 against your asset list to confirm coverage.
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
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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 lookupCVE-2021-22291 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
- High
- CVSS
- 8.5 (4.0)
- Known Exploited
- No
- Published
Vector: CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:A/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N
CNA and ADP enrichment extracted from CVE v5
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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:4.0/AV:N/AC:L/AT:N/PR:L/UI:A/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N——Primary CVE scoreVulnerability scoring details
Base CVSS 4.0 score
8.5HighVector: CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:A/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N
Source materials
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.