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CVE-2021-37630

22
FAUCET Score

CVE-2021-37630 describes a vulnerability in Nextcloud Circles versions prior to 0.19.15, 0.20.11, and 0.21.4, where any user could join a "Secret Circle" without owner approval, leading to private information disclosure. With a CVSS score of 6.5 (Medium), this flaw has a low attack complexity and requires low privileges, resulting in high confidentiality impact. There is no evidence of active exploitation, public exploit code (Metasploit, Nuclei, ExploitDB), or significant community discussion surrounding this CVE.

Impacted Technologies

VendorProductVersion(s)CPE
< 0.19.5CPE matchmatch criteria
cpe:2.3:a:nextcloud:circles:*:*:*:*:*:*:*:*
>= 0.20.0, < 0.20.11CPE matchmatch criteria
cpe:2.3:a:nextcloud:circles:*:*:*:*:*:*:*:*
>= 0.21.0, < 0.21.4CPE matchmatch criteria
cpe:2.3:a:nextcloud:circles:*:*:*:*:*:*:*:*

CVSS Data

CVSS version used by this source: 3.1

6.5MEDIUM

CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:N

Attack Vector
NETWORK
Attack Complexity
LOW
Privileges Required
LOW
User Interaction
NONE
Scope
UNCHANGED
Confidentiality Impact
HIGH
Integrity Impact
NONE
Availability Impact
NONE
Exploitability Score
2.8
Impact Score
3.6
CvssVersion
3.1

Exploit Intelligence

EPSS Score
1.20%
Probability of exploitation in next 30 days
EPSS Percentile
65.0%
Percentile rank of EPSS score among Peer Group
As of 2026-07-27
Model: v2026.06.15
This CVE's current EPSS score of 0.0120 is in the 79th percentile among its peer group of 21,974 CVEs.

Social Chatter

The average CVE in this peer group has 0.0 Twitter, 0.0 Reddit, 0.1 Bluesky, 0.0 Mastodon, and 0.1 GitHub mentions.

Media Mentions

No media coverage found for this CVE.

The average CVE in this peer group has 0.0 InfoSec Media, 0.0 Vendor Blog, and 0.0 Security Researcher mentions.

Remediation

Patch Available

Vendor Patches (1)

github_advisorypatch availablevia nvd_reference
View patch

References

github.com / nextcloud/circles/pull/768
PatchThird Party Advisory
github.com / nextcloud/security-advisories/security/advisories/GHSA-56j9-3rj4-wvgm
Third Party Advisory
hackerone.com / reports/1257624
Permissions RequiredThird Party Advisory