CWE-203Weakness · CWE-203

CVE-2019-25337

CRITICAL · 9.8 CVSS v3.1 Published 2026-02-12
Mitigation only
No fix yet — a mitigation exists. There is no fixed release. A documented workaround reduces exposure in the meantime.
See remediation →
100/100
Remediation priority · Urgent
Public exploit Remotely reachable No privileges Zero-click

Official description Straight from the sourceThe vendor's or NVD's own wording, published unedited. Authoritative, but often terse — it says what broke, rarely what to do.

NVD · unedited
OwnCloud 8.1.8 contains a username enumeration vulnerability that allows remote attackers to discover user accounts by manipulating the share.php endpoint. Attackers can send crafted GET requests to /index.php/core/ajax/share.php with a wildcard search parameter to retrieve comprehensive user information.

Technical summary Written by usOur analysis, written from the advisory, the CVSS vector and the affected-version data. It adds context the advisory leaves out, and never invents facts that are not in the source.

dbcve analysis · high confidence

OwnCloud 8.1.8 contains a username enumeration vulnerability in the /index.php/core/ajax/share.php endpoint. Remote attackers can send crafted GET requests with wildcard search parameters to retrieve a comprehensive list of valid user accounts, enabling targeted brute-force attacks or further exploitation.

MitigationUpgrade OwnCloud 8.1.8 to a patched version. As a compensating control, implement web application firewall rules or network-level access restrictions to limit exposure to the share.php endpoint until the upgrade is completed.

Verify against the referenced sources before acting — the references below are authoritative for this CVE, this summary is not.

CVSS breakdown How the score is builtThe industry scoring standard. It rates how the flaw is reached, what it takes to exploit, and what an attacker gains — the score is derived from those, not the other way round.

From the vector
Attack vector
Network
Complexity
Low
Privileges
None
User interaction
None
Scope
Unchanged
Confidentiality
High
Integrity
High
Availability
High

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

Am I affected? How to checkSteps we derive from the advisory and the affected-version data, so you can decide whether this CVE reaches your setup. They are a guide, not a scan — your own configuration is the authority.

dbcve checks

Work through these to decide whether this CVE applies to you.

  1. Verify OwnCloud version
    Check the installed OwnCloud version by reviewing the version.php file in the OwnCloud root directory or by accessing the ownCloud admin panel under 'Settings' > 'General' > 'Version'. Compare the installed version to the affected range (8.1.8).
    Affected if The installed version is 8.1.8 and has not been patched.
  2. Confirm share functionality is enabled
    Navigate to the OwnCloud admin panel and verify whether the sharing feature (user sharing) is enabled under 'Settings' > 'Sharing'. Alternatively, check the config/config.php file for the 'shareapi_enabled' setting.
    Affected if User sharing is enabled, making the vulnerable share.php endpoint accessible and the enumeration possible.
  3. Test the vulnerable endpoint
    Send a crafted GET request to /index.php/core/ajax/share.php with a wildcard parameter (for example, ?search= or ?pattern=*) using a tool like curl or a web browser. Observe if the response returns a list of valid usernames.
    Affected if The endpoint returns a list of valid user accounts in the response, confirming the vulnerability is present and exploitable.
  4. Check network access to the endpoint
    Review firewall rules, web server access controls, or network segmentation to determine if the share.php endpoint is exposed to untrusted networks or the public internet.
    Affected if The endpoint is accessible from untrusted networks without authentication, increasing the risk of exploitation.

A user is affected if OwnCloud version 8.1.8 is running, user sharing is enabled, and the share.php endpoint is accessible, allowing attacker to enumerate valid usernames.

Generated from the published advisory. Verify against your own configuration.

Check your environment

Paste your version and any relevant configuration and it will be compared against the affected criteria above. Do not include secrets or credentials.

AI-assisted, checked against the advisory. Informational, not a guarantee.

Remediation Closing itWhat it takes to close this. Where a vendor fix exists we point at it; where none exists we say so plainly, and can build one. Effort estimates are scoped from the advisory, not from your codebase.

From vendor data
Mitigation available No clean upgrade yet — mitigate in the meantime
Mitigation

Upgrade OwnCloud 8.1.8 to a patched version. As a compensating control, implement web application firewall rules or network-level access restrictions to limit exposure to the share.php endpoint until the upgrade is completed.

Have this fixed Scoped from the published advisory
  • Consultation4.0 h
  • Implementation8.0 h
  • Testing4.0 h
  • Review / QA2.0 h
18.0 hours of engineering $3,200
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Scan for this in your stack

Free · runs locally
dbcve dependency scanner

Check whether your project pulls in CVE-2019-25337 — or any other known-vulnerable package — straight from your lock files. Free and open source; it runs locally and uploads nothing.

References Go to the primary sourcePrimary sources — vendor advisories, patches and trackers. Where our summary and a reference disagree, the reference wins.

Primary sources

Practitioner notes

Contributed

Peer-ranked notes from engineers who’ve handled CVE-2019-25337 in production — separate from our analysis above.

No notes yet

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What this is

A place for practitioners to share what actually worked: a mitigation you’ve tested, a configuration change, a version- or environment-specific caveat, or a link to a verified patch. The most useful notes rise to the top as peers upvote them, so the signal stays high.

What belongs here
  • Verified mitigations, workarounds, and config changes
  • Version or environment caveats, and links to real fixes
  • No weaponised exploit code, or anything meant to cause harm
  • No spam, self-promotion, credentials, or personal data