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CVE-2020-4421: IBM WebSphere Application Liberty 19.0.0.5 through 20.0.0.4 could allow an authenticated user using openidc...

IBM WebSphere Application Liberty 19.0.0.5 through 20.0.0.4 could allow an authenticated user using openidconnect to spoof another users identify. IBM X-Force ID: 180084.

MediumCVSS 5Not KEV-listedUpdated
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Glexia's TakeAutomated analysismoderate

Security readout for executives and security teams

Plain-English summary

This flaw affects IBM WebSphere Application Server Liberty deployments using OpenID Connect. An authenticated user could potentially impersonate another user, creating account-trust and authorization risk. The published severity is medium, with high attack complexity and limited impact ratings, but identity spoofing can matter in sensitive applications.

Executive priority

Treat as a moderate identity-risk issue. It is not shown as actively exploited, but affected OpenID Connect applications should be remediated during normal vulnerability cycles, faster for high-value business systems.

Technical view

CVE-2020-4421 covers IBM WebSphere Application Server Liberty 19.0.0.5 through 20.0.0.4. The issue is an authenticated OpenID Connect identity spoofing vulnerability. The CVSS 3.0 score is 5.0, with network attack vector, low privileges required, high complexity, no user interaction, and low confidentiality, integrity, and availability impact.

Likely exposure

Exposure is most likely in applications running affected Liberty versions and using OpenID Connect authentication. Systems not using OpenID Connect, or running outside 19.0.0.5 through 20.0.0.4, are not shown as affected by the provided sources.

Exploitation context

The provided sources do not show active exploitation, and the CVE is not listed as KEV. Exploitation requires an authenticated user and high complexity, which lowers broad opportunistic risk but does not remove insider or compromised-account concern.

Researcher notes

Evidence is limited to IBM and CVE records. The sources identify spoofing, affected Liberty versions, and CVSS details, but do not provide public technical root cause, exploit procedure, or explicit fixed version details in the bundle.

Mitigation direction

  • Review IBM support notice 6205926 for the official corrected Liberty level.
  • Upgrade affected Liberty deployments according to IBM vendor guidance.
  • Prioritize systems using OpenID Connect for sensitive or privileged applications.
  • Review identity-provider and application authorization logs for suspicious impersonation indicators.
  • Limit access to applications using affected OpenID Connect flows where feasible.

Validation and detection

  • Inventory WebSphere Application Server Liberty versions across production and staging.
  • Confirm whether OpenID Connect is enabled on each Liberty deployment.
  • Flag versions 19.0.0.5 through 20.0.0.4 for remediation review.
  • Verify remediation against IBM advisory guidance, not assumed fixed versions.
  • Check authentication logs for unusual user switching or unexpected identity claims.
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-2020-4421 mapping review

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Vulnerability profileCVE Program record
Severity
Medium
CVSS
5 (3.0)
Known Exploited
No
Published

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

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
5CVSS 3.0MediumCVSS:3.0/A:L/I:L/AV:N/AC:H/S:U/C:L/PR:L/UI:N/RL:O/E:U/RC:C1.63.4Primary CVE score

Vulnerability scoring details

Base CVSS 3.0 score

5Medium
CVSS 3.0 vector shape for CVE-2020-4421Attack VectorAttack ComplexityPrivileges RequiredUser InteractionScopeConfidentiality ImpactIntegrity ImpactAvailability Impact

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

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
IBMWebSphere Application Server Liberty20.0.0.4, 19.0.0.5Listed
Weakness

CWE details

No CWE listed

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