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Unauthenticated command injection in Collabora Online Built-in CODE Server for Nextcloud
CVE-2026-110447 is an operating-system command injection vulnerability affecting Collabora Online Built-in CODE Server, distributed as the Nextcloud richdocumentscode app, in versions before 26.4.303. When the bundled CODE service is not running, the app's proxy handler incorporates request-controlled values into a shell command used to start the service without adequate escaping. An unauthenticated remote attacker can submit a crafted HTTP request that executes arbitrary commands with the web server account's privileges. The vulnerable handler executes directly through the web server, independently of Nextcloud's application-loading logic. Standalone Collabora Online deployments are unaffected. Exploitation occurred during September and October 2026. This vulnerability is distinct from CVE-2025-66208.
What it means and what to do now: patch path, interim mitigations, and the assume-compromise checklist.
What an attacker gets, and what they’ve been doing with it.
Successful exploitation compromises the confidentiality, integrity, and availability of resources accessible to the web server account. Attackers can read or modify accessible data, install web shells, maintain remote access, and disrupt services. Observed compromises included web shell deployment and retrieval of configuration data containing database credentials, service-mailbox credentials, application keys, and secrets. Stolen credentials may expose associated resources within those accounts' permissions. Exploitation does not inherently confer root privileges; administrative privilege escalation and lateral movement were not established in the described incidents.
If you can’t patch tonight, do this now.
If an immediate update is unavailable, completely remove richdocumentscode; disabling it through Nextcloud alone does not prevent exploitation because its proxy handler remains directly executable. Restrict external access to affected installations using perimeter or reverse-proxy controls, minimize Internet exposure, and isolate suspected compromised systems. Apply least privilege to the web server account, restrict access to sensitive configuration data, and monitor unexpected file changes, processes, and connections. Keeping the CODE service running is not a reliable mitigation because restarts, upgrades, and crashes can recreate the exploitable condition.
Patch, then assume compromise.
Upgrade richdocumentscode to version 26.4.303 or later, or completely remove the app. Installations running Nextcloud 29 or earlier must upgrade to a supported Nextcloud release compatible with the corrected app or remove the component. Investigate previously exposed systems even after updating: preserve evidence, review request and security logs, check application integrity, remove unauthorized web shells, and assess credential exposure and post-compromise activity. Rotate potentially exposed credentials and application secrets from a trusted environment, revoking and replacing compromised keys or certificates where necessary. Rebuild compromised systems from trusted sources when integrity cannot be established. Patching alone does not remove existing persistence or invalidate stolen secrets.
2 exploits validated by Mallory's analysis. Hidden: 3 rejected by Mallory's analysis as not a working exploit.
Products and vendors Mallory has correlated with this vulnerability. Open in Mallory to drill down to specific CPE configurations and version ranges.
128 sources tracked across advisories, community write-ups, and news. New activity surfaces here as Mallory finds it.