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CVE Record

CVE-2021-20366: IBM Cloud Pak for Applications 4.3 is vulnerable to cross-site scripting.

IBM Cloud Pak for Applications 4.3 is vulnerable to cross-site scripting. This vulnerability allows users to embed arbitrary JavaScript code in the Web UI thus altering the intended functionality potentially leading to credentials disclosure within a trusted session. IBM X-Force ID: 195037.

MediumCVSS 5.4Not KEV-listedUpdated
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Glexia's TakeAutomated analysismoderate

Security readout for executives and security teams

Plain-English summary

IBM Cloud Pak for Applications 4.3 has a Web UI cross-site scripting flaw. A lower-privileged user could embed JavaScript that runs in another trusted session, potentially exposing credentials or changing UI behavior. The business risk is meaningful where the product is still deployed and reachable by users.

Executive priority

Prioritize remediation if Cloud Pak for Applications 4.3 is still in use. This is not a critical infrastructure-level emergency based on the provided evidence, but credential exposure through a trusted enterprise UI can create downstream business risk.

Technical view

CVE-2021-20366 is an XSS issue in IBM Cloud Pak for Applications 4.3. The CVSS 3.0 score is 5.4, with network attack vector, low privileges required, user interaction required, changed scope, and low confidentiality and integrity impact. Availability impact is not indicated.

Likely exposure

Exposure is limited to IBM Cloud Pak for Applications version 4.3, specifically its Web UI. Risk is higher where many users can authenticate, where administrative users use the same interface, or where the UI is reachable from broad internal networks.

Exploitation context

The source bundle does not show CISA KEV listing or a cited active-exploitation claim. The CVSS temporal vector includes exploit-code maturity as high, but that is not the same as confirmed active exploitation. Treat this as a credible XSS risk, not proven mass exploitation.

Researcher notes

The provided data names only IBM Cloud Pak for Applications 4.3. No CWE is supplied. Do not broaden impact to other Cloud Pak products without vendor evidence. Fixed version and detailed mitigation are not present in the bundle, so validation should anchor on IBM advisory status.

Mitigation direction

  • Identify any IBM Cloud Pak for Applications 4.3 deployments.
  • Review IBM advisory 6471337 for official remediation or upgrade guidance.
  • Restrict Web UI access to trusted networks and necessary users.
  • Reduce unnecessary low-privileged accounts with Web UI access.
  • Monitor vendor guidance because fixed-version details are not included in the bundle.

Validation and detection

  • Confirm deployed IBM Cloud Pak for Applications versions from asset records.
  • Verify whether the Web UI is reachable by non-administrative users.
  • Review logs for unexpected UI content changes or suspicious credential activity.
  • Check whether IBM advisory remediation has been applied.
  • Confirm compensating access controls around the Web UI.
Prepared
Confidence
high
Sources
4

Public sources used

Generated from the cited source records. This long-tail analysis has not been individually reviewed by a named human.

Potential ATT&CK relevance

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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CVE-2021-20366 mapping review

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Vulnerability profileCVE Program record
Severity
Medium
CVSS
5.4 (3.0)
Known Exploited
No
Published

Vector: CVSS:3.0/PR:L/UI:R/I:L/AC:L/A:N/S:C/AV:N/C:L/E:H/RC:C/RL:O

Official CVE source material

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.

1CVSS vectors
0Timeline events
0ADP providers
3Source links

CVSS vector scores

1 official score

We 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.

ScoreVersionSeverityVectorExploitImpactSource
5.4CVSS 3.0MediumCVSS:3.0/PR:L/UI:R/I:L/AC:L/A:N/S:C/AV:N/C:L/E:H/RC:C/RL:O2.32.7Primary CVE score

Vulnerability scoring details

Base CVSS 3.0 score

5.4Medium
CVSS 3.0 vector shape for CVE-2021-20366Attack VectorAttack ComplexityPrivileges RequiredUser InteractionScopeConfidentiality ImpactIntegrity ImpactAvailability Impact

Vector: CVSS:3.0/PR:L/UI:R/I:L/AC:L/A:N/S:C/AV:N/C:L/E:H/RC:C/RL:O

Attack Vector
NetworkAdjacentLocalPhysical
Attack Complexity
LowHigh
Privileges Required
NoneLowHigh
User Interaction
NoneRequired
Scope
ChangedUnchanged
Confidentiality Impact
HighLowNone
Integrity Impact
HighLowNone
Availability Impact
HighLowNone

Source materials

Affected products

Products and packages named in the record

VendorProductVersion / packageStatus
IBMCloud Pak for Applications4.3Listed
Weakness

CWE details

No CWE listed

CWE links open Glexia weakness intelligence pages with official CWE context, developer remediation guidance, and related CVE mappings.