CVE-2021-37630

mediumpriority · track · 26EPSS 0.012 · 68 %ileEUUS

grimoire priorityP3 · Track

Exploitable?

—

no known exploitation

Likely / severe?

1.20% (68th) EPSS

CVSS 4 · medium

Is it mine?

6 products

Check your exposure

Who says so?

3 sources

cnnvd · enisa_euvd · nvd

EPSS · scored 2026-10-27

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.

cvss

Technical severity, 0–10. One row per scoring source.

6.5

010

base score 0–10 · higher = more severe · hover a vector to decode

v2.04mediumAV:N/AC:L/Au:S/C:P/I:N/A:Nprimary · NVD / NIST USexploitability 8 · impact 2.9

v3.16.5mediumCVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:Nprimary · NVD / NIST USexploitability 2.8 · impact 3.6

v3.16.5mediumCVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:Nsecondary · ENISA EU

v3.16.5mediumCVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:Nsecondary · security-advisories@github.comexploitability 2.8 · impact 3.6

v3.16mediumCVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:N/E:Usecondary · CVSS-BT (t0sche)

weaknesses

The CWE weakness classes this flaw belongs to.

CWE-639USprimary

affected products (6)

Products and version ranges known to be affected.

nextcloud security-advisories≤ < 0.19.15enisa_euvdEU
nextcloud security-advisories0.20.0, → 0.20.11enisa_euvdEU
nextcloud security-advisories0.21.0, → 0.21.4enisa_euvdEU
nextcloud circles< 0.19.5nvdUScpe:2.3:a:nextcloud:circles:*:*:*:*:*:*:*:*
nextcloud circles0.20.0 → 0.20.11nvdUScpe:2.3:a:nextcloud:circles:*:*:*:*:*:*:*:*
nextcloud circles0.21.0 → 0.21.4nvdUScpe:2.3:a:nextcloud:circles:*:*:*:*:*:*:*:*

also known as (2)

Other names and identifiers for this entity.

sources

Which sources assert this record, and when.

cnnvd enisa_euvd nvd NVD CVE.org MITRE

published 2021-09-07modified 2026-06-17

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references (11)

External citations — patches, advisories, analysis.

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