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CVE Record

CVE-2021-20517: IBM WebSphere Application Server Network Deployment 8.5 and 9.0 could allow a remote authenticated attacker...

IBM WebSphere Application Server Network Deployment 8.5 and 9.0 could allow a remote authenticated attacker to traverse directories. An attacker could send a specially-crafted URL request containing "dot dot" sequences (/../) to read and delete arbitrary files on the system. IBM X-Force ID: 198435.

MediumCVSS 6.4Not 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 Network Deployment 8.5 and 9.0. A logged-in remote attacker could abuse directory traversal handling to read and delete files on the server. The risk is material because deletion can disrupt applications, but exploitation requires authentication and high attack complexity.

Executive priority

Treat this as a moderate-priority enterprise middleware issue. It is not reported as actively exploited in the provided sources, but arbitrary file deletion can create outage risk on business systems running affected WebSphere ND versions.

Technical view

CVE-2021-20517 is a directory traversal issue in IBM WebSphere Application Server ND 8.5 and 9.0. IBM describes specially crafted URL requests containing dot-dot sequences as enabling arbitrary file read and deletion. CVSS v3.0 score is 6.4, with network attack vector, low privileges required, high complexity, low confidentiality impact, and high integrity impact.

Likely exposure

Exposure is limited by the provided sources to IBM WebSphere Application Server Network Deployment 8.5 and 9.0. Risk exists where authenticated users can reach the affected WebSphere service over the network, especially shared enterprise environments with broad low-privilege access.

Exploitation context

The source bundle does not show CISA KEV listing or active exploitation evidence. Public sources identify the vulnerability class and impact, but do not provide evidence here that exploitation is occurring in the wild.

Researcher notes

The bundle does not include CWE mapping or exact fixed builds. Analysis should stay anchored to IBM's advisory and X-Force entry. The key constraints are authenticated access, network reachability, high attack complexity, and potential arbitrary file read and deletion impact.

Mitigation direction

  • Review IBM advisory for the applicable fix pack or interim fix.
  • Prioritize remediation for internet-facing or broadly accessible authenticated deployments.
  • Restrict access to WebSphere administrative and application interfaces where feasible.
  • Review account access and remove unnecessary low-privilege authenticated users.
  • Back up critical application and configuration files before remediation work.

Validation and detection

  • Inventory WebSphere Application Server ND 8.5 and 9.0 deployments.
  • Confirm each deployment's fix level against IBM vendor guidance.
  • Identify which authenticated user groups can access affected services.
  • Review logs for unusual file read or deletion activity.
  • Confirm file permissions limit WebSphere process access where operationally feasible.
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-2021-20517 mapping review

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Vulnerability profileCVE Program record
Severity
Medium
CVSS
6.4 (3.0)
Known Exploited
No
Published

Vector: CVSS:3.0/UI:N/A:L/C:L/I:H/AV:N/AC:H/S:U/PR:L/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
6.4CVSS 3.0MediumCVSS:3.0/UI:N/A:L/C:L/I:H/AV:N/AC:H/S:U/PR:L/RL:O/E:U/RC:C1.64.7Primary CVE score

Vulnerability scoring details

Base CVSS 3.0 score

6.4Medium
CVSS 3.0 vector shape for CVE-2021-20517Attack VectorAttack ComplexityPrivileges RequiredUser InteractionScopeConfidentiality ImpactIntegrity ImpactAvailability Impact

Vector: CVSS:3.0/UI:N/A:L/C:L/I:H/AV:N/AC:H/S:U/PR:L/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 ND8.5, 9.0Listed
Weakness

CWE details

No CWE listed

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