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TI-2025-40967 Aliases CVE-2025-66556

Nextcloud talk allows participants to blindly delete poll drafts of other users by ID

Priority LOW 20CWE-639Published · Updated

Key facts

Attack vector
Network
Privileges required
Low
User interaction
None
Attack complexity
Low
Impact type
Security bypass
Confidentiality · integrity · availability
None · Low · None
Fix status
Fixed

Attack profile from CVSS 3.1 · NVD. Fix status from CNA. Impact type from CWE-639.

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.

Why it matters now

Exploitation None reported CISA SSVC · not in CISA KEV
EPSS 0.00272 19th percentileScored 2026-11-07
Fix Fixed security-advisories (nextcloud): 20.1.8, 21.1.2

SSVC decision points

CISA ADP · SSVC 2.0.3

Exploitation
None
Automatable
No
Technical impact
Partial

The decision (Track, Attend, Act) also depends on your mission and well-being impact; see CISA's SSVC guide.

Affected products

VendorProductAffected versionsFixed inStatusSource
nextcloudsecurity-advisoriesbefore 20.1.8; 21.0.0-beta.1 to before 21.1.220.1.8, 21.1.2Patch availableCNA
  • security-advisories Vendornextcloud Affected before 20.1.8; 21.0.0-beta.1 to before 21.1.2 Fixed in 20.1.8, 21.1.2 Patch available CNA

CPE configurations NVD · 1

CPEVersionsRoleVendor
cpe:2.3:a:nextcloud:talk:*:*:*:*:*:*:*:*20.0.0 to before 20.1.8; 21.0.0 to before 21.1.2Vulnerablenextcloud
  • cpe:2.3:a:nextcloud:talk:*:*:*:*:*:*:*:* Versions 20.0.0 to before 20.1.8; 21.0.0 to before 21.1.2 Vulnerable ·nextcloud

Remediation

  • Fix · CNA security-advisories (nextcloud) Fixed in 20.1.8, 21.1.2

Timeline

  1. 2026-10-02 Threatist record created from CVE-2025-66556

References

Patch 3

Advisory 1

  • TI-2022-08697 Open Redirect in Nextcloud Talk CVSS 3.1MEDIUM 6.1
  • TI-2021-18019 Geolocation preview links can be set to arbitrary links in nextcloud talk CVSS 3.1MEDIUM 6.1
  • TI-2023-24170 Password of talk conversations can be bruteforced in Nextcloud CVSS 3.1MEDIUM 4.3
  • TI-2022-08700 Exposure of Private Personal Information to an Unauthorized Actor in Nextcloud Talk CVSS 3.1MEDIUM 4.3
  • TI-2020-06598 Code injection in Nextcloud Talk CVSS 3.1CRITICAL 9.9
  • TI-2023-08722 Passcode bypass on Talk-Android app CVSS 3.1LOW 2.1
See all 19 →

Sources

This product uses the NVD API but is not endorsed or certified by the NVD. Sources and licences