7.5

CVE-2021-32727: nextcloud Improper Certificate Validation

CVSS: 7.5v3.1HighModified
Published 12-07-2021Last modified 03-08-2024
Open JSON

Vulnerability summary

CVE-2021-32727 is a high (CVSS 7.5) Improper Certificate Validation vulnerability in nextcloud. EPSS estimates a 0.73% chance of exploitation in the next 30 days, higher than 53.4% of scored vulnerabilities.

Overall risk
30/100
0100
Medium · default modelHow is this calculated?
CVSS score
7.5/10
010
High · v3.1 (NVD)
EPSS score
0.73%
0%100%
Low · 0.00 pp in 30 days
KEVNot listedIn no KEV catalog
RansomwareNone recordedNo known use recorded
Public exploits0No public exploits recorded

Timeline

  1. 12-07-2021
    PublishedVulnerability first disclosed.
  2. 03-08-2024
    Last modifiedVulnerability information updated.

Description

Nextcloud Android Client is the Android client for Nextcloud. Clients using the Nextcloud end-to-end encryption feature download the public and private key via an API endpoint. In versions prior to 3.16.1, the Nextcloud Android client skipped a step that involved the client checking if a private key belonged to a previously downloaded public certificate. If the Nextcloud instance served a malicious public key, the data would be encrypted for this key and thus could be accessible to a malicious actor. The vulnerability is patched in version 3.16.1. As a workaround, do not add additional end-to-end encrypted devices to a user account.

CVSS metrics

3 scores · 2 sources · 2 versions

EPSS trend

Probability

0.73%

Chance of exploitation in the next 30 days

Percentile

53%

Versus all other CVEs

30-day change

0.00 pp

From 0.73% on 19-09-2026

19-09-202619-10-2026
EPSS score
0.73%

Known exploited

Compare KEV catalogs

Not in any of the 3 tracked catalogs.

Public exploits

0 found

No public exploits indexed.

Weaknesses

CWE · root cause

Affected systems

Nextcloud2 products

1 vendor · 2 products

References

4 links