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CVE-2021-37630

Secret Circle can be joined without approval in Nextcloud Circles

MEDIUM
6.5
CVSS Score
Published: September 7, 2021 at 08:00 PM UTC
Updated: June 17, 2026 at 04:00 AM UTC
1 product affected across 1 vendorCircles

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Severity
MEDIUM6.5
Exploit prediction
EPSS 1%

Description

Nextcloud Circles is an open source social network built for the nextcloud ecosystem. In affected versions the Nextcloud Circles application allowed any user to join any "Secret Circle" without approval by the Circle owner leaking private information. It is recommended that Nextcloud Circles is upgraded to 0.19.15, 0.20.11 or 0.21.4. There are no workarounds for this issue.

Affected

Our own answer: ranges merged, affected separated from platform-only, with confidence and review flags.

Circles· Nextcloudnextcloud-app
95%
v < 0.19.50.20.0 ≤ v < 0.20.110.21.0 ≤ v < 0.21.4
Affected range stops below 0.19.5, so it looks safe — our inference, not a vendor statement
Affected range stops below 0.20.11, so it looks safe — our inference, not a vendor statement
Affected range stops below 0.21.4, so it looks safe — our inference, not a vendor statement

Remediation

No guide yet

No remediation guidance has been written for this CVE yet. What the record does show:

Patch and advisory references

References (3)

x_refsource_MISCPatchThird Party Advisory
Source: [email protected]
https://github.com/nextcloud/circles/pull/768
x_refsource_CONFIRMThird Party Advisory
Source: [email protected]
https://github.com/nextcloud/security-advisories/security/advisories/GHSA-56j9-3rj4-wvgm
x_refsource_MISCPermissions RequiredThird Party Advisory
Source: [email protected]
https://hackerone.com/reports/1257624

CVSS

6.5MEDIUMGitHub_M
Attack Vector
NETWORK
Complexity
LOW
Privileges
LOW
User Interaction
NONE
Scope
UNCHANGED
Confidentiality
HIGH
Integrity
NONE
Availability
NONE
Vector?

Quick Info

StatusMODIFIED
CWE
CWE-639

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