CVE-2021-43817 json
Reflected Cross-Site-Scripting vulnerability in Collabora Online
published 2021-12-13 4 y ago modified 2026-06-17 4 mo ago also EUVD-2021-30700
- cvss
- 8.2
- version 3.1, CNA
- cisa kev
- Not listed
- not in CISA's catalog
- epss
- 0.7%
- EPSS 0.7% chance of exploitation in 30 days, percentile 52%
- public exploits
- 0
- none known
Summary
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.
Patch / fix
- collabora online 4.2.20, 6.4.16
Exploit prediction
0.67% chance of exploitation in the next 30 days, higher than 52% of all scored CVEs (FIRST EPSS, 2026-11-08).
CVSS scores
| assigned by | version | score | vector |
|---|---|---|---|
| CNA | 3.1 | 8.2 | CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:H/A:N |
| NVD | 3.1 | 6.1 | CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N |
| NVD | 2.0 | 4.3 | AV:N/AC:M/Au:N/C:N/I:P/A:N |
Affected products
- CollaboraOnline online
Classification
- Weakness
-
- CWE-79 Improper Neutralization of Input During Web Page Generation
References
-
github.com
/CollaboraOnline/online/security/advisories/GHSA-7f6h-v9mx-58q9
third-party-advisory
Sources
- CVE List CVE-2021-43817
- NVD CVE-2021-43817
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