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Fencer Vulns
medium 6.5

CVE-2021-22877 json

A missing user check in Nextcloud prior to 20.0.6 inadvertently populates a user's own credentials for other users external storage configu…

published 2021-03-03 5 y ago modified 2026-06-17 4 mo ago also EUVD-2021-10012

cvss
6.5
version 3.1, NVD
cisa kev
Not listed
not in CISA's catalog
epss
1.7%
EPSS 1.7% chance of exploitation in 30 days, percentile 77%
public exploits
0
none known

Summary

A missing user check in Nextcloud prior to 20.0.6 inadvertently populates a user's own credentials for other users external storage configuration when not already configured yet.

Patch / fix

  • nextcloud nextcloud_server 20.0.6

Vendor advisories

What the vendors themselves say about their products: affected, fixed or not affected, and what to do.

red hat product security vex CVE-2021-22877 updated

nextcloud: Stored credentials accessible by other users

  • Red Hat All currently supported Red Hat products
    not affected: vulnerable code not present

Red Hat CSAF VEX © Red Hat, Inc., from https://security.access.redhat.com/data/csaf/v2/vex/; changed: reduced to product statuses and remediations. CC BY 4.0 · csaf

Exploit prediction

1.69% chance of exploitation in the next 30 days, higher than 77% of all scored CVEs (FIRST EPSS, 2026-11-08).

Exploits and checks

  • github.com https://github.com/nextcloud/server/issues/24600 referenced PoC, tagged "exploit" by a source, unverified

CVSS scores

assigned by version score vector
NVD 3.1 6.5 CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:U/C:H/I:H/A:N
NVD 2.0 5.5 AV:N/AC:L/Au:S/C:P/I:P/A:N

Affected products

  • n/a Nextcloud Server

Classification

Weakness

References

Sources

Fencer Vulns keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.