CVE-2026-110447: Collabora Online – Built-in CODE Server OS Command Injection Vulnerability

In short

Collabora Collabora Online – Built-in CODE Server has a weakness classified as OS command injection (CWE-78). CISA added it to its Known Exploited Vulnerabilities catalog on 2026-10-23. NVD lists CVSS 4.0 at 9.2 CRITICAL.

What it is

“Collabora Collabora Online – Built-in CODE Server when used within the NextCloud platform contains an OS command injection vulnerability that allows for remote code execution when the CODE server isn't running.” — CISA KEV, retrieved 2026-11-01

“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.” — NVD, retrieved 2026-11-01

Who is affected

Collabora Collabora Online – Built-in CODE Server. NVD lists the following versions as affected:

• Versions before 26.4.303

Exploitation status

CISA KEV added: 2026-10-23. Known ransomware campaign use: Not reported by CISA. Due date CISA set for US federal civilian agencies: 2026-10-26.

Scores

NVD CVSS 4.0: 9.2 CRITICAL; vector CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X; source [email protected].

EPSS by FIRST: 73.31%; percentile 99.46; score date 2026-10-31. EPSS estimates the probability of exploitation in the next 30 days.

CWE: CWE-78.

Timeline

CISA required action

“Apply mitigations in accordance with vendor instructions, ensuring compliance with CISA’s BOD 26-04 Prioritizing Security Updates Based on Risk (see URL in Notes) guidance and CISA’s “Forensics Triage Requirements” (see URL in Notes). Follow applicable BOD 26-04 guidance for cloud services or discontinue use of the product if mitigations are unavailable. Stakeholders are responsible for evaluating each asset's internet exposure and ensuring adherence to BOD 26-04 patching guidelines.” — CISA KEV

What to do

• Confirm whether you run Collabora Collabora Online – Built-in CODE Server and which version.
• Apply the vendor update or mitigation in the advisory.
• Follow CISA’s required action.
• Review the vendor guidance on signs of compromise.
• Track the fix through completion.

References

• Vendor Advisory: https://help.nextcloud.com/t/to-collabora-built-in-user-update-asap/250516
• NVD detail
• CVE.org record
• CISA KEV catalog

Sources and dates

CISA Known Exploited Vulnerabilities Catalog, version 2026.10.30; retrieved 2026-11-01. CISA KEV data: CC0 1.0. No endorsement by CISA.

NVD retrieved: 2026-11-01. This product uses the NVD API but is not endorsed or certified by the NVD.

EPSS scores by FIRST; score date 2026-10-31.