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Fencer Intel
medium 6.8

CVE-2020-8227 json

Missing sanitization of a server response in Nextcloud Desktop Client 2.6.4 for Linux allowed a malicious Nextcloud Server to store files o…

published 6y ago modified 4mo ago also EUVD-2020-29099

cvss
6.8
version 3.1, NVD
cisa kev
Not listed
not in CISA's catalog
epss
25.8%
EPSS 25.8% chance of exploitation in 30 days, percentile 97%
public exploits
0
none known

Summary

Missing sanitization of a server response in Nextcloud Desktop Client 2.6.4 for Linux allowed a malicious Nextcloud Server to store files outside of the dedicated sync directory.

Patch / fix

  • nextcloud desktop 2.6.5
  • nextcloud-desktop Debian 14, Debian 13, Debian 12 3.0.1-1

debian advisories DEBIAN-CVE-2020-8227

Is CVE-2020-8227 in your stack? Fencer shows which of your repositories are affected as soon as an advisory lands, and opens the fix as a pull request.

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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-2020-8227 updated cvss 5.1

nextcloud: missing sanitization of a server response leads to store files outside of dedicated sync directory

  • 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

25.77% chance of exploitation in the next 30 days, higher than 97% of all scored CVEs (FIRST EPSS, 2026-11-09).

Exploits and checks

  • hackerone.com https://hackerone.com/reports/590319 referenced PoC, tagged "exploit" by a source, unverified
  • nextcloud.com https://nextcloud.com/security/advisory/?id=NC-SA-2020-032 referenced PoC, tagged "exploit" by a source, unverified

CVSS scores

assigned by version score vector
NVD 3.1 6.8 CVSS:3.1/AV:N/AC:L/PR:H/UI:R/S:U/C:H/I:H/A:H
NVD 2.0 7.1 AV:N/AC:H/Au:S/C:C/I:C/A:C

Affected products

  • n/a Desktop Client

Classification

Weakness
  • CWE-22 Improper Limitation of a Pathname to a Restricted Directory

References

Sources

Fencer Intel 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.