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CVE-2021-32745: Reflected Cross-Site-Scripting vulnerability

• Severity: medium (CVSS 6.1 v3.1)
• Exploited in the wild: not listed in CISA KEV
• EPSS: 0.6% probability of exploitation in the next 30 days
• Public exploit or detection template: none known
• Published: 2021-07-21 · updated 2026-06-17
• Weakness: CWE-79

Description

Collabora Online is a collaborative online office suite. A reflected XSS vulnerability was found in Collabora Online prior to version 6.4.9-5. 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. The issue is patched in Collabora Online 6.4.9-5. Collabora Online 4.2 is not affected.

Affected products

• CollaboraOnline online: from 4.2 (excl.) before 6.4.9-5 — fixed in 6.4.9-5

How to fix

Upgrade to a fixed version: CollaboraOnline online 6.4.9-5. Check the vendor advisory for mitigations.

References

• https://github.com/CollaboraOnline/online/security/advisories/GHSA-w536-654v-cjj9
• https://github.com/CollaboraOnline/online/security/advisories/GHSA-w536-654v-cjj9

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