Improper authentication in nextcloud Files Lock
Key facts
- Attack vector
- Network
- Privileges required
- Low
- User interaction
- None
- Attack complexity
- Low
- Impact type
- Security bypass
- Confidentiality · integrity · availability
- Low · Low · Low
- Fix status
- No fix listed
Attack profile from CVSS 3.0 · CNA. Fix status from CNA. Impact type from CWE-287.
Summary
Any authenticated user can lock or unlock files they do not own by targeting absolute WebDAV paths of other users. The DAV plugin resolves files from the absolute request URI without verifying that the path segment matches the authenticated session user. This enables: Cross-user manual locks : attacker locks a victim's files, blocking writes (PUT/MOVE/DELETE, editor saves). Lock-token disclosure: the app returns the lock token to unauthorized callers, enabling them to remove token-based locks (client locks) of other users.
Why it matters now
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
Remediation
No fixed version listed by the sources yet.
Timeline
- 2026-10-02 Threatist record created from CVE-2026-82980
- 2026-10-03 Alias added: GHSA-3vwx-p83m-w7p5
References
More nextcloud vulnerabilities
- 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
Sources
- CVE-2026-82980 · CVE Program
- CVE-2026-82980 · NVD
- FIRST EPSS
- GHSA-3vwx-p83m-w7p5 · GitHub Advisory Database · CC BY 4.0
This product uses the NVD API but is not endorsed or certified by the NVD. Sources and licences