CVE-2026-77165: File Lock Privilege Escalation Vulnerability

CVE-2026-77165 Overview

CVE-2026-77165 is an improper access control vulnerability [CWE-284] affecting a file-locking mechanism. File owners cannot unlock TYPE_TOKEN locks that were placed by other users. The affected files remain permanently locked, and no recovery path exists outside of direct database intervention.

The issue was disclosed through HackerOne Report #3770482. An authenticated remote attacker with low privileges can trigger the condition, resulting in a persistent availability impact on affected resources.

Critical Impact
An authenticated user can place a TYPE_TOKEN lock on a file that the legitimate owner cannot release, causing a permanent denial of access to that resource.

Affected Products

Product details were not specified in the published CVE record
Refer to the linked HackerOne report for vendor-specific scope
Confirm exposure by reviewing internal use of TYPE_TOKEN file-lock APIs

Discovery Timeline

2026-09-21 - CVE-2026-77165 published to the National Vulnerability Database
2026-09-22 - Last updated in NVD database

Technical Details for CVE-2026-77165

Vulnerability Analysis

The vulnerability resides in the authorization logic that governs file lock release. When a user places a TYPE_TOKEN lock on a file, the unlock routine validates that the requesting user matches the lock originator rather than checking file ownership. This blocks the file owner from reclaiming control of their own resource.

The result is a persistent availability failure. Locked files cannot be modified, released, or recovered through the normal application interface. Administrators must manipulate the underlying database to clear the lock state, which introduces operational risk and downtime.

Root Cause

The root cause is missing or incorrect access control enforcement on the unlock code path [CWE-284]. The authorization check treats the lock creator as the sole authority for release. It does not grant file owners an override for TYPE_TOKEN locks, breaking the expected ownership model.

Attack Vector

Exploitation requires network access and a low-privileged authenticated account. The attacker places a TYPE_TOKEN lock on any file they can access. The file owner then loses the ability to unlock, edit, or otherwise recover the file through the application. No user interaction is required from the victim.

Code examples are not available for this issue. See the HackerOne Report #3770482 for reproduction details.

Detection Methods for CVE-2026-77165

Indicators of Compromise

Files that remain in a locked state despite unlock requests from the verified owner
Application logs showing TYPE_TOKEN lock creation by accounts that are not the file owner
Support tickets or user reports about files that cannot be edited or released
Database entries in the lock table where lock_owner differs from file_owner for extended periods

Detection Strategies

Query the lock table for TYPE_TOKEN entries where the lock creator does not match the file owner
Alert on unlock attempts that fail with authorization errors against files owned by the requester
Baseline normal lock lifetimes and flag TYPE_TOKEN locks that persist beyond expected durations

Monitoring Recommendations

Forward application and database audit logs to a centralized analytics platform for correlation
Track counts of active TYPE_TOKEN locks per user to identify anomalous lock creation patterns
Monitor helpdesk categories related to locked-file recovery for a spike in volume

How to Mitigate CVE-2026-77165

Immediate Actions Required

Review the linked HackerOne Report #3770482 to confirm applicability to your deployment
Audit the current lock table for TYPE_TOKEN entries not owned by the file owner and clear stale locks
Restrict lock creation privileges to trusted user roles where feasible

Patch Information

No vendor advisory or patch reference was published in the CVE record at the time of writing. Consult the upstream project or vendor for a fixed release that enforces file-owner override on TYPE_TOKEN unlock operations.

Workarounds

Provide administrators with a supported procedure to clear TYPE_TOKEN locks via the database until a patch is available
Limit which authenticated users can place TYPE_TOKEN locks through role or group restrictions
Implement a maximum lock duration policy that automatically releases stale TYPE_TOKEN locks

bash

# Example administrative query to identify orphaned TYPE_TOKEN locks
# Adapt table and column names to the affected product schema
SELECT file_id, lock_owner, file_owner, created_at
  FROM file_locks
 WHERE lock_type = 'TYPE_TOKEN'
   AND lock_owner <> file_owner;