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TI-2021-18020 Aliases CVE-2021-41181

Nextcloud Talk app exposes chat messages on lockscreen

Priority LOW 12CWE-200Published · Updated

Key facts

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

Attack profile from CVSS 3.1 · CNA. Fix status from CNA. Impact type from CWE-200 and CWE-287.

Summary

Nextcloud talk is a self hosting messaging service. In versions prior to 12.3.0 the Nextcloud Android Talk application did not properly detect the lockscreen state when a call was incoming. If an attacker got physical access to the locked phone, and the victim received a phone call the attacker could gain access to the chat messages and files of the user. It is recommended that the Nextcloud Android Talk App is upgraded to 12.3.0. There are no known workarounds.

Why it matters now

Exploitation None reported CISA SSVC · not in CISA KEV
EPSS 0.00309 23rd percentileScored 2026-11-07
Fix Fixed security-advisories (nextcloud): 12.3.0

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 12.3.012.3.0Patch availableCNA
  • security-advisories Vendornextcloud Affected before 12.3.0 Fixed in 12.3.0 Patch available CNA

CPE configurations NVD · 1

CPEVersionsRoleVendor
cpe:2.3:a:nextcloud:talk:*:*:*:*:*:android:*:*before 12.3.0Vulnerablenextcloud
  • cpe:2.3:a:nextcloud:talk:*:*:*:*:*:android:*:* Versions before 12.3.0 Vulnerable ·nextcloud

Remediation

  • Fix · CNA security-advisories (nextcloud) Fixed in 12.3.0

Timeline

  1. 2026-10-02 Threatist record created from CVE-2021-41181

References

Patch 1

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