Read the docs
TI-2026-32987 Aliases CVE-2026-45159

Authorization bypass in nextcloud security-advisories

Priority LOW 16CWE-639Published · Updated

Key facts

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

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

Summary

Nextcloud is an open source content collaboration platform. From versions 1.15.0 to before 1.15.4, 1.16.0 to before 1.16.3, 1.17.0 to before 1.17.1, and 1.18.0 to before 1.18.1, a malicious user with access to an end-to-end encrypted files drop link was able to also drop files into other end-to-end encrypted folders of the share owner. Reading and modifying of other files was not possible. This issue has been patched in versions 1.15.4, 1.16.3, 1.17.1, 1.18.1, and 2.0.0-rc.7.

Why it matters now

Exploitation None reported CISA SSVC · not in CISA KEV
EPSS 0.00203 10th percentileScored 2026-11-07
Fix Fixed security-advisories (nextcloud): 1.15.4, 1.16.3, 1.17.1 +1

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-advisories1.15.0 to before 1.15.4; 1.16.0 to before 1.16.3; 1.17.0 to before 1.17.1; 1.18.0 to before 1.18.11.15.4, 1.16.3, 1.17.1, 1.18.1Patch availableCNA
  • security-advisories Vendornextcloud Affected 1.15.0 to before 1.15.4; 1.16.0 to before 1.16.3; 1.17.0 to before 1.17.1; 1.18.0 to before 1.18.1 Fixed in 1.15.4, 1.16.3, 1.17.1, 1.18.1 Patch available CNA

Remediation

  • Fix · CNA security-advisories (nextcloud) Fixed in 1.15.4, 1.16.3, 1.17.1, 1.18.1

Timeline

  1. 2026-10-02 Threatist record created from CVE-2026-45159

References

Other 3

  • 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