# CVE-2025-59716: OwnCloud Guests - Information Disclosure

> Live exploitation tracking for CVE-2025-59716 by the CrowdSec Live Exploit Tracker, built from real-world attack data crowdsourced from CrowdSec's global network.

Page: https://tracker.crowdsec.net/cves/CVE-2025-59716

## Key facts

- **Exploitation phase:** Limited Exploitation. The vulnerability is known but shows very limited attacker interest or exploitation activity.
- **CVSS score:** 5.3
- **Public exploit available:** Yes
- **Affected products:** OwnCloud Guests
- **Weaknesses:** CWE-200 (Exposure of Sensitive Information to an Unauthorized Actor); CWE-203 (Observable Discrepancy)
- **Tags:** web_application, file_sharing

## Description

OwnCloud Guests before 0.12.5 allows unauthenticated user enumeration via the /apps/guests/register/{email}/{token} endpoint. Because of insufficient validation of the supplied token in showPasswordForm, the server responds differently when an e-mail address corresponds to a valid pending guest user rather than a non-existent user.

## CrowdSec analysis

[CVE-2025-59716](https://euvd.enisa.europa.eu/vulnerability/CVE-2025-59716) is an information disclosure vulnerability in ownCloud Guests before version 0.12.5 that allows unauthenticated attackers to enumerate valid guest user email addresses via the /apps/guests/register/{email}/{token} endpoint. By exploiting insufficient token validation, attackers can determine whether a specific email address is registered as a pending guest, potentially aiding in targeted phishing or social engineering attacks.

CrowdSec has been tracking this vulnerability and its exploits since 1st of April 2026.

Insights from the CrowdSec network reveal that the attackers trying to exploit CVE-2025-59716 are composed of a fairly even mix of opportunistic and targeted actors. Some attackers employ preliminary reconnaissance, while others use indiscriminate scanning.
CrowdSec data also reveals a clear uptick in attacks involving CVE-2025-59716 over the past week. Activity is above the usual baseline, suggesting growing attention from attackers. This may reflect rising awareness, recent exploit releases, or expanded targeting efforts.

Attackers exploit the endpoint `/apps/guests/register/{email}/{token}` to enumerate valid guest users in ownCloud by observing responses to crafted requests with arbitrary email addresses and invalid tokens. This allows unauthenticated probing for existing guest accounts.

## Timeline

- 2025-11-05: CVE Published. CVE-2025-59716 is published to NVD.
- 2026-04-01: Rule Released. CrowdSec releases a rule to detect CVE-2025-59716 exploitation attempts against the CrowdSec Network.
- 2026-04-01: CrowdSec First Seen. CrowdSec observes in-the-wild exploitation of CVE-2025-59716 for the first time.

## References

- https://github.com/owncloud/guests
- https://gist.github.com/thesmartshadow/64ae0449e909174d0479a4f23657147f
- https://marketplace.owncloud.com/apps/guests
- https://github.com/projectdiscovery/nuclei-templates/blob/main/http/cves/2025/CVE-2025-59716.yaml

## Live exploitation data

The [Live Exploit Tracker page](https://tracker.crowdsec.net/cves/CVE-2025-59716) follows observed exploitation activity for CVE-2025-59716. [Request an API key](https://tracker.crowdsec.net/request-api-key) for full access to its exploitation timeline, attacking IP addresses and blocklists.