CVE-2021-32782Network attack vector

Stored script execution via unescaped circle names

Published Sep 7, 2021 · Updated Aug 3, 2024

Stored XSS in Nextcloud Circles allows remote authenticated users to run scripts in other users’ browsers through a crafted circle name. The shared-file browsing formatResult and formatSelection callbacks returned attacker-controlled circle.name values as HTML without escaping them. Exploitation requires another user to browse shared files with a browser that does not enforce Nextcloud’s Content Security Policy; modern CSP-capable browsers block the script.

CVSS severity5.8
Medium
EPSS probability0.83%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Stored XSS in Nextcloud Circles allows remote authenticated users to run scripts in other users’ browsers through a crafted circle name. The shared-file browsing formatResult and formatSelection callbacks returned attacker-controlled circle.name values as HTML without escaping them. Exploitation requires another user to browse shared files with a browser that does not enforce Nextcloud’s Content Security Policy; modern CSP-capable browsers block the script.

The record

CVE
CVE-2021-32782
Published
Sep 7, 2021
Updated
Aug 3, 2024
Vendor
Nextcloud GmbH
Product
Nextcloud Security Advisories
Classifications
CWE-79, T1059.007
Attack vector
network
Privileges
authenticated

Timeline

How it unfolded

  1. Sep 7, 2021CVE publishedPublication date reported by the CVE source.
  2. Aug 3, 2024Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

Compare your product and version with the public record. A matching version still requires validation against your environment.

Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=< 0.19.1
  2. Affected versionversion=>= 0.20.0, < 0.20.10
  3. Affected versionversion=>= 0.21.0, < 0.21.3

What conditions does exploitation require?

Attack vectornetwork
Required privilegesauthenticated

What is affected?

Nextcloud GmbH · Nextcloud Security Advisoriesversion=< 0.19.1; version=>= 0.20.0, < 0.20.10; version=>= 0.21.0, < 0.21.3

Published CVSS scores

5.4NIST NVDCVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:L/I:L/A:N
5.8GitHub, Inc.CVSS:3.1/AV:N/AC:H/PR:L/UI:R/S:C/C:H/I:N/A:N
3.5NIST NVDAV:N/AC:M/Au:S/C:N/I:P/A:N

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

Daily unique IPsNo honeypot observations are available for this CVE in the selected window.

No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-79Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting')
T1059.007Command and Scripting Interpreter: JavaScript

Public exploit references

No public exploit references are available in this record.

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

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Your stack

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