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CVE Record

CVE-2017-18872: An issue was discovered in Mattermost Server before 4.4.3 and 4.3.3.

An issue was discovered in Mattermost Server before 4.4.3 and 4.3.3. Attackers could reconfigure an OAuth app in some cases where Mattermost is an OAuth 2.0 service provider.

UnknownCVSS not scoredNot KEV-listedUpdated
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Glexia's TakeAutomated analysisunknown

Security readout for executives and security teams

Plain-English summary

Mattermost disclosed a flaw in older Mattermost Server versions that could let attackers reconfigure an OAuth application when Mattermost is used as an OAuth 2.0 service provider. Business impact depends on OAuth usage and permissions. The source bundle provides no CVSS score, detailed impact, patch notes beyond fixed versions, or exploitation evidence.

Executive priority

Prioritize remediation if the organization still runs legacy Mattermost and uses OAuth provider functionality. The issue is old, but OAuth app reconfiguration can affect trust relationships. If Mattermost is current and OAuth provider use is absent, urgency is lower after validation.

Technical view

CVE-2017-18872 affects Mattermost Server before 4.4.3 and 4.3.3. In some OAuth 2.0 service-provider configurations, an attacker could reconfigure an OAuth app. The public record does not define prerequisites, affected branches beyond the fixed-version statement, CWE, CVSS, or full remediation details.

Likely exposure

Exposure is most likely in legacy Mattermost Server deployments older than 4.4.3 or 4.3.3 that enabled Mattermost as an OAuth 2.0 service provider. Organizations on modern supported Mattermost versions are unlikely to be exposed, but should verify exact version history.

Exploitation context

The provided sources do not show CISA KEV listing, public exploitation, exploit code, or observed attacks. Treat active exploitation as unconfirmed. The available description indicates configuration tampering risk around OAuth applications, but not how access is gained or what privileges are required.

Researcher notes

Evidence is sparse. The CVE record gives a concise vulnerability description and fixed-version thresholds but omits CVSS, CWE, exploitability prerequisites, and detailed impact. Avoid assuming broad account takeover or active exploitation without additional vendor-confirmed detail.

Mitigation direction

  • Upgrade Mattermost Server to 4.4.3, 4.3.3, or a later supported release.
  • Check Mattermost security updates for any branch-specific upgrade guidance.
  • Inventory OAuth apps configured in Mattermost and remove unknown or unused entries.
  • Review OAuth app settings for unexpected redirect URIs, names, or ownership changes.
  • Prioritize migration if running unsupported legacy Mattermost versions.

Validation and detection

  • Confirm the deployed Mattermost Server version across all environments.
  • Determine whether Mattermost is configured as an OAuth 2.0 service provider.
  • Review OAuth application inventory for unauthorized configuration changes.
  • Check administrative logs for OAuth app changes during the exposure window.
  • Document whether fixed versions or later supported releases are deployed.
Prepared
Confidence
medium
Sources
3

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

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CVE-2017-18872 mapping review

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Vulnerability profileCVE Program record
Severity
Unknown
CVSS
Not scored
Known Exploited
No
Published
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.

0CVSS vectors
0Timeline events
0ADP providers
2Source links

CVSS and timeline data

No CVSS vectors or timeline events were available in the normalized CVE source material.

Source materials

Affected products

Products and packages named in the record

VendorProductVersion / packageStatus
n/an/an/aListed
Weakness

CWE details

No CWE listed

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