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CVE-2026-110447

From Exploited flaws, HARD’s guide to the flaws being used in attacks · Checked
This article is about a flaw in Collabora Online – Built-in CODE Server. For every flaw being used in attacks, see Exploited flaws.

CVE-2026-110447 is a security flaw in Collabora Online – Built-in CODE Server. Attackers can run their own code on Collabora Online – Built-in CODE Server. The US Cybersecurity and Infrastructure Security Agency (CISA) added it to its catalog of flaws known to be used in attacks on 23 Oct 2026.[1]

Collabora Online – Built-in CODE Server is business software or equipment. Most families won’t have it, but attackers break into it to get inside companies, and from there to what those companies hold about their customers, patients and staff. Fixed in version 26.4.303 of Collabora Online - Built-in CODE Server.

Description

CISA calls it an online – built-in CODE server OS command injection in Collabora Collabora Online – Built-in CODE Server. In its words: “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.”[1]

The CVE record adds: “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.”[2]

The underlying weakness is OS command injection (CWE-78), in MITRE’s list of common software weaknesses.

It scores 9.8 out of 10 on the Common Vulnerability Scoring System, which rates it critical, scored by NVD using CVSS 3.1.[2]

Affected versions

NVD’s record lists one fixed version: everything before it is affected.[2]

ProductFixed in
Collabora Online - Built-in CODE Server26.4.303

Most families won’t have Collabora Online – Built-in CODE Server; it’s for whoever looks after IT at work.

Exploitation

CISA added it to its catalog of known exploited vulnerabilities on 23 Oct 2026, 9 days after it was made public. CISA lists a flaw only when it has reliable evidence of it being exploited, and gave US federal agencies until 26 Oct 2026 to fix it.[1]

FIRST’s Exploit Prediction Scoring System, which estimates how likely a flaw is to be used in attacks in the next 30 days from what it sees across the internet, puts it at 73%. That’s in the top 1% of the flaws it scores.[4]

CISA assesses it as automatable: attackers can run it against many targets at once.

CISA doesn’t say who was attacked, or how.

Fix

Collabora has published a fix or advice.[3] CISA’s 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).”[1]

  1. Check whether you use it.Collabora Online – Built-in CODE Server is business software or equipment, so most families won’t have it. If you run a business, or work from home on company equipment, ask whoever looks after your IT.
  2. Send this page to your IT person.Ask them to confirm it’s fixed (fixed in version 26.4.303 of Collabora Online - Built-in CODE Server), or not in use. CISA gave US government agencies until 26 Oct 2026 to fix it.
  3. If it can’t be fixed, take it offline.CISA’s advice when there’s no fix is to stop using the product, or take it off the internet, until there is one.

You can’t fix someone else’s server, but you can watch for what follows a break-in like this: a breach notice, a password reset you didn’t ask for, or a scam message that knows things it shouldn’t. HARD watches for those for you and your family.

Timeline

DateEvent
The flaw is made public in the National Vulnerability Database, with a severity score of 9.8.[2]
CISA adds it to its catalog of flaws known to be used in attacks.[1]
CISA’s deadline for US government agencies to fix it.[1]
FIRST puts the odds of it being used in attacks in the next 30 days at 73%.[4]

See also

Other OS command injection flaws

  • CVE-2026-106931, EG Secure Solutions SiteGuard Server Edition: OS command injection ·
  • CVE-2026-83549, SonicWall SMA1000 Appliances: OS command injection ·
  • CVE-2026-49869, Kestra OSS: OSS OS command injection ·
  • CVE-2026-73570, Synacor Zimbra Collaboration Suite (ZCS): OS command injection ·
  • CVE-2026-16812, Arista VeloCloud Orchestrator: on-prem OS command injection ·

Added the same day

  • CVE-2026-114625, Arista VeloCloud Orchestrator: SQL injection ·

References

  1. ^ Cybersecurity and Infrastructure Security Agency. “Collabora Online – Built-in CODE Server OS Command Injection Vulnerability”. Known Exploited Vulnerabilities Catalog, added 23 Oct 2026.
  2. ^ National Institute of Standards and Technology. “CVE-2026-110447 Detail”. National Vulnerability Database, published 14 Oct 2026.
  3. ^ Collabora. Advisories and fixes: help.nextcloud.com, github.com.
  4. ^ FIRST. “Exploit Prediction Scoring System”. EPSS 0.733, percentile 99.5, 31 Oct 2026.
  5. CVE Program. “CVE-2026-110447”. The official CVE record.

This article is built from CISA’s catalog (version 2026.10.30), NVD’s record and FIRST’s scores, kept in HARD’s database and checked every morning. The plain English is HARD’s.