Vulnerability · CVE-2025-66556
Nextcloud talk is a video & audio conferencing app for Nextcloud.
Published Dec 5, 2025 · catalog updated Oct 15, 2026 · Nextcloud talk is a
Check if you run it
No confirmed exploitation is on record for CVE-2025-66556. EPSS is 0.25%. Act only if a listed version of Nextcloud talk is a is installed.
- Severity
- Medium4.3
- Known exploitation
- Not in CISA/VulnCheck KEV
- EPSS
- 0.25%
- Remediation
- Advisory link
- Affected products
- cpe nextcloud/talk
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.
Are you affected?
Enter the version you run. The result uses only the ranges stored on this record.
The check returns affected, not affected, or incomplete. It does not guess a version that is missing from the record.
- cpe nextcloud/talkversion unspecified
How to fix CVE-2025-66556
Recommended remediation
A patch or advisory reference is linked. Open the original publisher for availability by product version.
Official advisories
What to do
Three questions, each answered from this record only. Confirm the vendor advisory before you patch.
Should you patch?
No confirmed exploitation is on record for CVE-2025-66556. EPSS is 0.25%. Act only if a listed version of Nextcloud talk is a is installed.
Which versions are affected?
Affected version ranges are not on this record. Compare the installed version with the linked vendor advisory before you change production.
What should an analyst verify?
CWE-639: Authorization Bypass Through User-Controlled Key. EPSS 0.25%. There is no CISA KEV listing. No Exploit-DB or Metasploit reference is linked. Use the source links for the original advisory.
Code
The project this record applies to. Exploit listings stay in References.
Timeline
Detection, updates, and resolution for this record.
Dec 5, 2025 · NIST NVD
Detected
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.
Oct 15, 2026 · NIST NVD
Updated
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.
Sources
- CVE.orgVulnerability recordCVE-2025-66556
Official CVE identifier
cve.org - FIRST EPSSExploitation probabilityCVE-2025-66556
30-day exploitation probability 0.3%
first.org - NIST NVDVulnerability recordCVE-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 is fixed in 20.1.8 and 21.1
nvd.nist.gov
References
Freshness
Last verified in this catalog Oct 18, 2026. Significant claims (KEV, EPSS, CVSS, affected ranges) come from the source rows above — open the original publisher for the authoritative advisory.