CVE-2021-32733: nextcloud nextcloud_server Cross-site Scripting
Vulnerability summary
CVE-2021-32733 is a medium (CVSS 6.1) Cross-site Scripting vulnerability in nextcloud nextcloud_server. EPSS estimates a 1.11% chance of exploitation in the next 30 days, higher than 65.2% of scored vulnerabilities.
Timeline
- 12-07-2021PublishedVulnerability first disclosed.
- 03-08-2024Last modifiedVulnerability information updated.
Description
Nextcloud Text is a collaborative document editing application that uses Markdown. A cross-site scripting vulnerability is present in versions prior to 19.0.13, 20.0.11, and 21.0.3. The Nextcloud Text application shipped with Nextcloud server used a `text/html` Content-Type when serving files to users. Due the strict Content-Security-Policy shipped with Nextcloud, this issue is not exploitable on modern browsers supporting Content-Security-Policy. The issue was fixed in versions 19.0.13, 20.0.11, and 21.0.3. As a workaround, use a browser that has support for Content-Security-Policy.
CVSS metrics
3 scores · 2 sources · 2 versions- CVE.orgCNA4.8MediumCVSS:3.1/AV:N/AC:H/PR:L/UI:R/S:U/C:N/I:H/A:NDiffers
EPSS trend
Probability
1.11%
Chance of exploitation in the next 30 days
Percentile
65%
Versus all other CVEs
30-day change
0.00 pp
From 1.11% on 19-09-2026
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
3 links- github.com/nextcloud/security-advisories/security/advisories/GHSA-x4w3-jhcr-57pqX Refsource CONFIRMThird Party Advisory