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Vulnerability record · public intelligence
CVE-2021-37631
MEDIUM

Circle can be accessed by non-Circle members in Nextcloud Deck

Published Sep 7, 2021 · Updated Nov 3, 2026

Severity · CVSSMEDIUM · Not scored
Known exploitationNot listed
EPSS / likelihood1.28%
QFinch risk scoreNot available

Original summary

Normalized public record · Updated Nov 3, 2026

Circle can be accessed by non-Circle members in Nextcloud Deck

Publisher and source text is retained separately from QFinch interpretation.

QFinch assessment

Deck is an open source kanban style organization tool aimed at personal planning and project organization for teams integrated with Nextcloud. In affected versions the Deck application didn't properly check membership of users in a Circle. This allowed other users in the instance to gain access to boards that have been shared with a Circle, even if the user was not a member of the circle. It is recommended that Nextcloud Deck is upgraded to 1.5.1, 1.4.4 or 1.2.9. If you are unable to update it is advised to disable the Deck plugin.

Evidence: public source records

Affected products

Affected scope reported by the available public evidence
Affected package, product or rangeFix status
Consult the referenced vendor advisory for affected versions.Consult source advisory

Matching a version is only one part of assessing exposure. QFinch has not assessed your environment on this public page.

Remediation

Apply the vendor-supported fixed release or mitigation, then verify the affected component is no longer reachable.

  1. Confirm the affected product and reachable code path exist in your environment.
  2. Apply the vendor-supported patch or mitigation from the primary advisory.
  3. Rescan the exact deployed revision and retain verification evidence.
Review primary references

Evidence coverage

FIRST-EPSSCVE-LIST-V5
SSVC priority
LOW
Confidence
Not available
Aliases
None reported

Scores appear only when corresponding evidence exists. Missing data is never interpreted as zero risk.

Sources and record history

  1. Security advisory ↗
  2. Source repository ↗
  3. hackerone.com ↗
  4. hackerone.com ↗

Record history

Published Sep 7, 2021 · Last refreshed Nov 3, 2026