Security readout for executives and security teams
Plain-English summary
This issue affects Phoenix Contact FL MGUARD 1102 and 1105 devices on listed firmware versions. A highly privileged user could use a manipulated certificate file to inject HTML into management interfaces, creating a cross-site scripting risk. Business impact appears limited but relevant for regulated or sensitive operational networks.
Executive priority
Treat this as a moderate-priority remediation item. It is not described as actively exploited, but affected security gateway management interfaces should be controlled and updated according to vendor guidance.
Technical view
CVE-2021-34582 is a CWE-79 XSS vulnerability in FL MGUARD web-based management and REST API handling of manipulated certificate files. CVSS 3.1 is 4.8: network reachable, low complexity, high privileges required, user interaction required, changed scope, low confidentiality and integrity impact, no availability impact.
Likely exposure
Exposure is likely limited to Phoenix Contact FL MGUARD 1102 and 1105 running versions 1.4.0, 1.4.1, or 1.5.0, where management or REST API access is reachable by high-privileged users.
Exploitation context
The bundle does not show CISA KEV listing or active exploitation evidence. Exploitation requires high privileges and user interaction, which lowers urgency, but the issue sits in device management surfaces that may be sensitive in operational environments.
Researcher notes
Evidence is limited to the CVE description and referenced advisory metadata in the provided bundle. The affected list in the bundle duplicates 1.4.0, while the description names 1.4.0, 1.4.1, and 1.5.0; validate against the vendor advisory.
Mitigation direction
- Inventory FL MGUARD 1102 and 1105 devices and record firmware versions.
- Check Phoenix Contact and VDE guidance for fixed firmware or official workarounds.
- Restrict web management and REST API access to trusted administrative networks.
- Limit high-privileged accounts to personnel who require certificate management access.
- Avoid importing certificate files unless their source and integrity are trusted.
Validation and detection
- Confirm whether any FL MGUARD 1102 or 1105 devices run versions 1.4.0, 1.4.1, or 1.5.0.
- Verify management interfaces are not exposed beyond intended administrative networks.
- Review who has high privileges on affected device management interfaces.
- Check logs or change records for recent certificate imports on affected devices.
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 lookupCVE-2021-34582 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
- 4.8 (3.1)
- Known Exploited
- No
- Published
Vector: CVSS:3.1/AV:N/AC:L/PR:H/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:H/UI:R/S:C/C:L/I:L/A:N1.72.7Primary CVE scoreVulnerability scoring details
Base CVSS 3.1 score
4.8MediumVector: CVSS:3.1/AV:N/AC:L/PR:H/UI:R/S:C/C:L/I:L/A:N
Source materials
- CVE List V5 sourceCVE List V5
- https://cert.vde.com/en/advisories/VDE-2021-046/CVE 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.