Auth bypass in Nextcloud Security-advisories
CVE-2025-66556
Nextcloud talk is a video & audio conferencing app for Nextcloud. Prior to 20.1.8 and 21.1.2, a participant with chat permissions was able to delete poll drafts of other participants within the conversation based on their numeric ID. This…
Vulnerability class: IDOR (Insecure Direct Object Reference)
EPSS: 0.002 (10.7th percentile) — read the EPSS interpretation.
CVSS v3 metric
CVSS v3 base score 3.5 (Low). Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:U/C:N/I:L/A:N.
Affected products
- Nextcloud Security-advisories — versions < 20.1.8, >= 21.0.0-beta.1, < 21.1.2
- Nextcloud Talk
Weakness classification (CWE)
References
- security-advisories@github.com (x_refsource_CONFIRM, Patch, Vendor Advisory)
- security-advisories@github.com (Patch, x_refsource_MISC, Issue Tracking)
- security-advisories@github.com (Patch, x_refsource_MISC)
- security-advisories@github.com (x_refsource_MISC, Issue Tracking, Vendor Advisory)
Frequently asked questions
- What is CVE-2025-66556?
- CVE-2025-66556 is a low-severity vulnerability in Nextcloud Security-advisories, classified under Authorization Bypass Through User-Controlled Key. CVSS score: 3.5/10. Published 2025-12-05.
- How severe is CVE-2025-66556?
- Low severity. CVSS v3 base score is 3.5 out of 10.