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Full vulnerability report · 2026
CVE-2026-110447High confidence

Collabora Online – Built-in CODE Server OS Command Injection Vulnerability

Collabora · Collabora Online – Built-in CODE Server

9.2CriticalCVSS 4.0
Recommended action
Protect now

CISA confirms exploitation in the wild and lists 2026-10-26 as the remediation due date.

Fix not verified
R
Operational reassessment

Published severity in operational context

Open reassessment dashboard →
Published severityCriticalOperational priority:Critical, unchanged from published severity.unchanged

Evidence used

  • CISA confirms exploitation in the wild.
  • The selected CVSS metric records a network-reachable, unauthenticated path with no user interaction.
  • EPSS is 2.28% for the current model date.

Compensating controls

  • Restrict the affected network interface to trusted sources where business-safe.
  • Increase monitoring for the attack path and post-exploitation behaviour described in the report.

Verification

  1. Confirm that the asset runs Collabora Collabora Online – Built-in CODE Server and falls inside the recorded affected range.
  2. Recheck the vendor advisory before scheduling a change because no verified fixed version is currently retained.
  3. Validate exposure, authentication requirements and compensating controls in the actual environment.
  4. Reopen this reassessment when CVSS, KEV, EPSS, exploit evidence or remediation changes.
Mitigation target: Within 3 daysRemediation target: Within 90 days

This automated reassessment organises public evidence. It does not know asset exposure, business impact or control effectiveness and does not replace CVSS or a human risk decision.

Optional official sources

National CERT insights
?CERT means Computer Emergency Response Team; CSIRT is the closely related term Computer Security Incident Response Team.

Choose official national sources for this report. Each advisory shows its original language. Your selection is remembered on this device and included in shared links.

Official European source

ENISA European Vulnerability Database

Official EUVD identifiers, advisory evidence and known-exploited context. Missing fields are not treated as evidence of low risk.

1 current
ENISA EUVD identifier

EUVD-2026-100780

CISA KEV mirrored by ENISA

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.

EUVD state
Present in the current official mapping
Known exploitation
Recorded by ENISA since 23 Oct 2026. Evidence sources: cisa_kev.
ENISA score
9.2 · CVSS 4.0
Advisory evidence
No linked advisory details stored yet
Recommended actionProtect now

CISA confirms exploitation in the wild and lists 2026-10-26 as the remediation due date.

Fix not verified
01

What, why and how

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.

What

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.

Why

Untrusted input is incorporated into an operating-system command without safe parameter handling.

How

An attacker operating through a network path may attempt exploitation without authentication or user interaction. If successful, the issue may execute code or commands in the affected security context.

What

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.

Why

Untrusted input is incorporated into an operating-system command without safe parameter handling.

How

An attacker operating through a network path may attempt exploitation without authentication or user interaction. If successful, the issue may execute code or commands in the affected security context.

02

Exploit reality and attack path

CVSS severity, EPSS forecast probability, public exploit material and CISA-confirmed exploitation are separate signals.

Observed exploitation
?Confirmed exploitation and public exploit material are separate signals. Attacks can occur without public proof-of-concept or exploit code.
Confirmed in the wild

CISA added this CVE to its Known Exploited Vulnerabilities catalogue on 2026-10-23.

Public PoC / exploit material
?Confirmed exploitation and public exploit material are separate signals. Attacks can occur without public proof-of-concept or exploit code.
None recorded

No exploit-tagged reference or CISA SSVC proof-of-concept state is currently recorded. Research may still exist outside the structured feeds.

Likely attack path
a network path → Improper Neutralization of Special Elements used in an OS Command ('OS Command Injection') → execute code or commands in the affected security context
Attack surface
Network
Privileges required
None: unauthenticated exploitation is possible
User interaction
None
Attack complexity
Low: no specialised conditions are recorded
Security boundary
Not a CVSS 4.0 base metric
Weakness
?CWE means Common Weakness Enumeration: a standard category for the underlying weakness.
CWE-78 ↗

CWE-78: Improper Neutralization of Special Elements used in an OS Command ('OS Command Injection'). The product constructs all or part of an OS command using externally-influenced input from an upstream component, but it does not neutralize or incorrectly neutralizes special elements that could modify the intended OS command when it is sent to a downstream component.

CVSS vector
?CVSS means Common Vulnerability Scoring System. The vector records the metric values used to calculate technical severity.
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

Common Vulnerability Scoring System 4.0: the compact vector below is decoded into plain language.

AVNetworkAttack vector: The vulnerable component can be reached over a network.ACLowAttack complexity: No specialised conditions are required beyond attacker-controlled input.ATPresentAttack requirements: A particular deployment or execution condition must be present.PRNonePrivileges required: The attacker does not need an account or existing privileges.UINoneUser interaction: No action by another user is required.VCHighVulnerable-system confidentiality: A successful attack can cause a major loss.VIHighVulnerable-system integrity: A successful attack can cause a major loss.VAHighVulnerable-system availability: A successful attack can cause a major loss.SCNoneSubsequent-system confidentiality: No direct loss is represented by this metric.SINoneSubsequent-system integrity: No direct loss is represented by this metric.SANoneSubsequent-system availability: No direct loss is represented by this metric.
Post-exploitation / living off the land
After compromise, an attacker may use built-in shells, scripting engines, scheduled tasks and native network utilities for discovery, persistence or movement. This is a plausible LoTL path, not evidence that it has occurred for every attack.
NetworkUnauthenticatedRemote code executionCWE-78CISA KEV
A

Official authority intelligence

Only matched European and national findings are included. Language selectors and unavailable sources are omitted.

ENISA EUVD · EUVD-2026-100780Known-exploited evidence recorded

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.

Official EUVD record ↗
BSI · German · WID-SEC-2026-4011Collabora Online Built-in CODE Server (NextCloud): Schwachstelle ermöglicht Ausführen von beliebigem Programmcode mit Benutzerrechten

Ein entfernter, anonymer Angreifer kann eine Schwachstelle in Collabora Collabora Online ausnutzen, um beliebigen Programmcode als Webserver-Benutzer auszuführen.

Official advisory ↗
CSIRT Italia · Italian · nextcloud-rilevato-sfruttamento-di-una-vulnerabilita-nel-componente-collabora-online-built-in-code-serverNextcloud: rilevato sfruttamento di una vulnerabilità nel componente Collabora Online Built-in CODE Server

La vulnerabilità identificata tramite la CVE-2026-110447 , di tipo ”OS Command Injection” e con CVSS v4.0 pari a 9.2, interessa il componente Collabora Online - Built-in CODE Server per Nextcloud. Questa vulnerabilità è dovuta a un’errata convalida di parametri di input nel file proxy.php. Un attaccante remoto non autenticato potrebbe sfruttare tale vulnerabilità per inviare richieste HTTP opportunamente predisposte al fine di iniettare comandi di sistema ed eseguirli con i privilegi dell’utenza associata al web server. Lo sfruttamento è possibile quando il servizio CODE integrato non è in esecuzione, ad esempio a seguito di un riavvio, di un aggiornamento o di un arresto anomalo. La vulnerabilità riguarda questa modalità di distribuzione del componente e non interessa i server Collabora Online installati separatamente. L’esecuzione di comandi può consentire di installare strumenti di accesso remoto, leggere o modificare le informazioni accessibili all’utenza del web server e compromettere la disponibilità del servizio sui sistemi interessati. L’acquisizione di credenziali e segreti applicativi potrebbe inoltre consentire ulteriori accessi alle risorse associate, nei limiti dei permessi concessi alle utenze compromesse.

Official advisory ↗
KISA KrCERT/CC · Korean · KNVD-7013美 CISA 발표 주요 Exploit 정보공유(Update. 2026-10-23)

Collabora Online – Built-in CODE Server OS Command Injection Vulnerability

Official advisory ↗
03

Patch and workaround

Operational remediation based on structured source evidence.

Status
?Patch availability is based on structured fixed-version fields and authoritative update references. If no fix is verified, check the vendor advisory before making a change.
Fix not verified
Affected
Collabora Online - Built-in CODE Server: < 26.4.303
Fixed
No fixed version is explicitly recorded in the structured CVE data.
Action
No verified patch reference is present in the current structured sources. Check the vendor advisory before making a change.
Workaround
No verified workaround is recorded. If business-safe, reduce exposure to the affected interface and allow only trusted sources until authoritative guidance is available.
04

Evidence and provenance

Published 14 Oct 2026 · Last source change 24 Oct 2026, 03:55 UTC · CWE-78 · Improper Neutralization of Special Elements used in an OS Command ('OS Command Injection')

CVE recordCVE.org · 5.2
CVSS sourceCNA
EPSS source
?The date BlackTree first stored a score for this CVE from the daily FIRST EPSS feed.
FIRST · tracked since 2026-10-14
European sourceENISA EUVD · EUVD-2026-100780
Product sourceCISA KEV
Remediation sourceCVE/CNA references
CWE sourceCNA
NVD statusNVD not scheduled

Core structured fields are present and their contributing authorities are shown above.

Material change intelligence

What changed after publication

View recent updates ↗
  1. ENISA known-exploited stateENISA EUVD now records this CVE in its known-exploited dataset.
    Before
    not listed in ENISA EUVD known-exploited dataset
    After
    listed in ENISA EUVD known-exploited dataset (EUVD-2026-100780)
    ENISA EUVD ↗
  2. BlackTree coverageBlackTree article coverage changed from no BlackTree article to 1 BlackTree article.
    Before
    no BlackTree article
    After
    1 BlackTree article
    BlackTree editorial ↗
  3. ENISA EUVD mappingEUVD-2026-100780 was added to the official ENISA EUVD mapping for this CVE.
    Before
    not recorded
    After
    {"euvdId":"EUVD-2026-100780"}
    ENISA EUVD ↗
  4. CISA KEV stateCISA KEV now confirms exploitation in the wild.
    Before
    not listed in CISA KEV
    After
    listed in CISA KEV since 2026-10-23
    CISA KEV ↗
  5. Catalogue recordCVE added to the BlackTree catalogue.
    CNA ↗
Material fields only · duplicate refreshes suppressed · history retained for the configured operational retention period
CVE published
Added to CISA KEV
ENISA EUVD · EUVD-2026-100780↗CISA KEV record↗CVE authority or vendor reference↗Official CVE record (CNA and ADP data)↗NVD record↗
Technical terms and abbreviations used in this report
CVE
Common Vulnerabilities and Exposures: the public identifier for one disclosed vulnerability.
CVSS
Common Vulnerability Scoring System: a technical severity framework; it is not patching priority by itself.
EPSS
Exploit Prediction Scoring System: FIRST's estimate of the probability that exploitation activity will be observed in the next 30 days; it is a forecast, not confirmation.
CWE
Common Weakness Enumeration: the standard category describing the underlying software or hardware weakness.
CNA
CVE Numbering Authority: an organisation authorised to assign and publish CVE records.
CISA ADP
Cybersecurity and Infrastructure Security Agency Authorized Data Publisher: structured enrichment added to a CVE record.
NVD
National Vulnerability Database: NIST's enrichment service for CVE records.
CERT / CSIRT
A computer security incident response team that publishes warnings or coordinates incident response.
PoC
Proof of concept: public material that demonstrates or helps reproduce exploitation.
CSAF
Common Security Advisory Framework: a machine-readable format for security advisories.
LoTL
Living off the land: abuse of legitimate tools or system functions during an attack.
Free version - for non-commercial use only.CVE-2026-110447 · cve.blacktree.nl