CVE-2025-66556 | BDVDB-2026-304101 Detail

nextcloudsecurity-advisories

Description#

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 is fixed in 20.1.8 and 21.1.2.

Impact#

Per CVSS v3.1: confidentiality impact none, integrity impact low, availability impact none. Attack vector: network.

Weaknesses#

CWE-639 Authorization Bypass Through User-Controlled Key

References#

Exploit#

No public exploit known

History#

Version 12025-12-05Record published in the CVE List.

Published

Published: 2025-12-05
Last modified: 2025-12-05

Vendor information

Vendor: nextcloud
Product: security-advisories

All nextcloud vulnerabilities

Score

3.5 Low

EPSS

less than 1%, Very Low

Estimated chance of exploitation in the next 30 days. EPSS percentile: 19.7.

KEV

Not listed in the CISA Known Exploited Vulnerabilities catalog.

Impact

Insecure Direct Object Reference

Action

No specific action is recorded in the source data. Check the references for vendor guidance.

Affected Systems

Vulnerable
< 20.1.8
Fixed
Not stated
Vulnerable
>= 21.0.0-beta.1, < 21.1.2
Fixed
Not stated

Scoring System

CVSS v4.0

Not available

CVSS v3.1

3.5 Low

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

Metric breakdown
Attack Vector	Network
Attack Complexity	Low
Privileges Required	Low
User Interaction	Required
Scope	Unchanged
Confidentiality	None
Integrity	Low
Availability	None

CVSS v3.0

Not available

CVSS v2

Not available

Source: CVE List v5 (record); CISA KEV (kev, action); FIRST EPSS (epss).