Nextcloud Desktop client does not verify received singed certificate in end-to-end encryption

published 2023-04-04 3 y ago modified 2026-06-17 4 mo ago also EUVD-2023-32618

cvss: 5.4; version 3.1, CNA
cisa kev: Not listed; not in CISA's catalog
epss: 0.4%; EPSS 0.4% chance of exploitation in 30 days, percentile 33%
public exploits: 0; none known

The Nextcloud Desktop Client is a tool to synchronize files from Nextcloud Server. Starting with version 3.0.0 and prior to version 3.7.0, by trusting that the server will return a certificate that belongs to the keypair of the user, a malicious server could get the desktop client to encrypt files with a key known to the attacker. This issue is fixed in Nextcloud Desktop 3.7.0. No known workarounds are available.

Patch / fix

fixed in 1 distros 1 links 1

nextcloud desktop 3.7.0

nextcloud-desktop Debian 14, Debian 13, Debian 12 3.7.0-1

debian advisories DEBIAN-CVE-2023-29000

github.com/nextcloud/desktop#4949 pull request

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-2023-29000 updated 2026-06-26

nextcloud: Multiple vulnerabilities

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

CISA SSVC

Exploitation: none
Automatable: no
Technical impact: partial
Assessed: 20 mo ago (2025-02-11)

Exploit prediction

0.39% chance of exploitation in the next 30 days, higher than 33% of all scored CVEs (FIRST EPSS, 2026-11-08).

CVSS scores

assigned by	version	score	vector
CNA	3.1	5.4	CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:L/I:L/A:N
NVD	3.1	6.5	CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:N

Affected products

nextcloud security-advisories

Classification

Weakness

CWE-295 Improper Certificate Validation

References

github.com /nextcloud/desktop/pull/4949
patch
github.com /nextcloud/security-advisories/security/advisories/GHSA-h82x-98q3-7534
vendor-advisory
hackerone.com /reports/1679267
permissions-required

Sources

CVE List CVE-2023-29000
NVD CVE-2023-29000

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.

Summary