CVE-2026-110447

Critical

Description

Collabora Online Built-in CODE Server before 26.4.303 (richdocumentscode), a Nextcloud app, allows remote code execution, as exploited in the wild in September and October 2026, a different vulnerability than CVE-2025-66208. This is an OS command injection in proxy.php when the CODE server isn't running (e.g., the product was recently restarted). The vulnerability is not present in standalone Collabora Online servers; only this deployment with CODE Server is affected.

References

https://github.com/CollaboraOnline/richdocumentscode/issues/354
https://help.nextcloud.com/t/to-collabora-built-in-user-update-asap/250516
https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2026-110447

Why this priority

Critical because this CVE is listed in CISA’s Known Exploited Vulnerabilities (KEV) catalog - confirmed active exploitation outranks every other signal.

CVSS score

9.8

CVSS severity

CRITICAL

EPSS score

—

EPSS percentile

—

CISA KEV

Yes - actively exploited

KEV remediation due

2026-10-26

Published

Oct 14, 2026

Last modified

Oct 30, 2026