CVE-2021-32726: nextcloud nextcloud_server Incorrect Ownership Assignment
Vulnerability summary
CVE-2021-32726 is a critical (CVSS 9.8) Incorrect Ownership Assignment vulnerability in nextcloud nextcloud_server. EPSS estimates a 1.78% chance of exploitation in the next 30 days, higher than 77.8% of scored vulnerabilities.
Advisory lineage
Upstream 0 · Downstream 1 · Related 1Timeline
- 12-07-2021PublishedVulnerability first disclosed.
- 03-08-2024Last modifiedVulnerability information updated.
Description
Nextcloud Server is a Nextcloud package that handles data storage. In versions prior to 19.0.13, 20.011, and 21.0.3, webauthn tokens were not deleted after a user has been deleted. If a victim reused an earlier used username, the previous user could gain access to their account. The issue was fixed in versions 19.0.13, 20.0.11, and 21.0.3. There are no known workarounds.
CVSS metrics
3 scores · 2 sources · 2 versions- CVE.orgCNA7.1HighCVSS:3.1/AV:N/AC:H/PR:L/UI:R/S:U/C:H/I:H/A:HDiffers
EPSS trend
Probability
1.78%
Chance of exploitation in the next 30 days
Percentile
78%
Versus all other CVEs
30-day change
0.00 pp
From 1.78% on 18-09-2026
Known exploited
Compare KEV catalogsNot in any of the 3 tracked catalogs.
Public exploits
0 foundNo public exploits indexed.
Weaknesses
CWE · root causeAffected systems
Nextcloud2 products
- nextcloud_server< 19.0.13 | ≥ 20.0.0, < 20.0.11 | ≥ 21.0.0, < 21.0.3
- security-advisories< 19.0.13 | ≥ 20.0.0, < 20.0.11 | ≥ 21.0.0, < 21.0.3
1 vendor · 2 products
References
4 links- github.com/nextcloud/security-advisories/security/advisories/GHSA-6qr9-c846-j8mgX Refsource CONFIRMThird Party Advisory