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TI-2026-81398 Aliases CVE-2026-77173

Nextcloud Files Confidential skips confidential marking

Priority LOW 19CWE-284Published · Updated

Key facts

Attack vector
Network
Privileges required
Low
User interaction
None
Attack complexity
Low
Impact type
Security bypass
Confidentiality · integrity · availability
Low · None · None
Fix status
No fix listed

Attack profile from CVSS 3.0 · CNA. Fix status from CNA. Impact type from CWE-284.

Summary

Nextcloud Files Confidential from 3.3.0 through 5.0.0 does not apply the confidential marking to DOCX or ODT files whose filename contains a # character. A user with low privileges can create such a file holding sensitive data, such as a credit card number, and it is not marked as confidential, which is an improper access control weakness (CWE-284).

Written with Claude Haiku 5.5 from the sources below · 2026-11-04

Description from the CNA

A user could create a docx or odt file with a # in the filename with confidential information such as a credit card number and have it not be marked as confidential.

Why it matters now

Exploitation None reported CISA SSVC · not in CISA KEV
EPSS 0.00213 11th percentileScored 2026-11-07
Fix No fix listed No fixed version in the sources yet

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
nextcloudFiles Confidential3.3.0 – 5.0.0—No fix listedCNA
  • Files Confidential Vendornextcloud Affected 3.3.0 – 5.0.0 Fixed in — No fix listed CNA

Remediation

The sources list no fixed version for Nextcloud Files Confidential.

Written with Claude Haiku 5.5 from the sources below · 2026-11-04

Timeline

  1. 2026-10-27 Threatist record created from CVE-2026-77173
  2. 2026-11-04 CISA SSVC decision points changed

References

Other 1

  • TI-2026-18211 Windmill < 1.615.0 Operator Role Missing Authorization Checks RCE CVSS 4.0HIGH 8.7
  • TI-2023-14838 NextCloud Cookbook's pull-checks.yml workflow is vulnerable to OS Command Injection CVSS 3.1HIGH 8.8
  • TI-2022-08650 Command Injection in Appointment Emails for Nextcloud Calendar CVSS 3.1CRITICAL 9.8
  • TI-2023-20855 Users can delete external storage mount points CVSS 3.1HIGH 7.7
  • TI-2023-11091 Nextcloud download permissions can be changed by resharer CVSS 3.1HIGH 7.5
  • TI-2023-10624 Nextcloud Server vulnerable to SSRF via filter bypass due to lax checking on IPs CVSS 3.1MEDIUM 5.3
See all 401 →

Sources

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