CVE-2021-43817

Reflected Cross-Site-Scripting vulnerability in Collabora Online

MEDIUM
6.1
CVSS Score
Published: December 13, 2021 at 07:45 PM UTC
Updated: June 17, 2026 at 04:11 AM UTC
2 products affected across 2 vendorsOnlineOnline

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Severity
MEDIUM6.1
Exploit prediction
EPSS 0.7%

Description

Collabora Online is a collaborative online office suite based on LibreOffice technology. In affected versions a reflected XSS vulnerability was found in Collabora Online. An attacker could inject unescaped HTML into a variable as they created the Collabora Online iframe, and execute scripts inside the context of the Collabora Online iframe. This would give access to a small set of user settings stored in the browser, as well as the session's authentication token which was also passed in at iframe creation time. Users should upgrade to Collabora Online 6.4.16 or higher or Collabora Online 4.2.20 or higher. Collabora Online Development Edition 21.11 is not affected.

Affected

Our own answer: ranges merged, affected separated from platform-only, with confidence and review flags.

v < 4.2.206.4.0 ≤ v < 6.4.16
Affected range stops below 4.2.20, so it looks safe — our inference, not a vendor statement
Affected range stops below 6.4.16, so it looks safe — our inference, not a vendor statement
v < 4.2.20v < 6.4.16
Affected range stops below 4.2.20, so it looks safe — our inference, not a vendor statement
Affected range stops below 6.4.16, so it looks safe — our inference, not a vendor statement

Remediation

No guide yet

No remediation guidance has been written for this CVE yet, and no fixed version or vendor advisory is recorded against it.

CVSS

Attack Vector
NETWORK
Complexity
LOW
Privileges
NONE
User Interaction
REQUIRED
Scope
CHANGED
Confidentiality
LOW
Integrity
LOW
Availability
NONE
Vector?

Quick Info

StatusMODIFIED
CWE
CWE-79

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