CVE-2025-66556 json
Nextcloud talk allows participants to blindly delete poll drafts of other users by ID
published 2025-12-05 11 mo ago modified 2026-10-15 24 d ago also EUVD-2025-201458
- cvss
- 3.5
- version 3.1, CNA
- cisa kev
- Not listed
- not in CISA's catalog
- epss
- 0.3%
- EPSS 0.3% chance of exploitation in 30 days, percentile 19%
- public exploits
- 0
- none known
Summary
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.
Patch / fix
- nextcloud talk 20.1.8, 21.1.2
CISA SSVC
- Exploitation
- none
- Automatable
- no
- Technical impact
- partial
- Assessed
- 11 mo ago
Exploit prediction
0.27% chance of exploitation in the next 30 days, higher than 19% of all scored CVEs (FIRST EPSS, 2026-11-08).
CVSS scores
| assigned by | version | score | vector |
|---|---|---|---|
| CNA | 3.1 | 3.5 | CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:U/C:N/I:L/A:N |
| NVD | 3.1 | 4.3 | CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:L/A:N |
Affected products
- nextcloud security-advisories
Classification
- Weakness
-
- CWE-639 Authorization Bypass Through User-Controlled Key
References
-
github.com
/nextcloud/spreed/pull/15532
issue-tracking, patch
-
github.com
/nextcloud/spreed/commit/bd68e80d1dea98d84c1d621c2c681238cf041725
patch
-
github.com
/nextcloud/security-advisories/security/advisories/GHSA-pr9f-vqgg-m2jh
patch, vendor-advisory
-
hackerone.com
/reports/3247386
issue-tracking, vendor-advisory
Sources
- CVE List CVE-2025-66556
- NVD CVE-2025-66556
Fencer Vulns keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.
CPEs and fixed versions use Anchore's correction of NVD's data: Added CPE configurations because not yet analyzed by NVD.