CVE-2026-75109: Determined API Authorization Bypass Flaw

CVE-2026-75109 Overview

CVE-2026-75109 is a missing authorization vulnerability [CWE-862] in Determined, an open-source deep learning training platform. The flaw exists in the API handlers for generic task lifecycle endpoints, specifically the kill, pause, and unpause operations. Authenticated users can invoke these endpoints against tasks owned by other users because the server does not verify ownership or permissions before executing the requested action. The vulnerability affects multi-tenant Determined deployments where several users share cluster resources for machine learning workloads.

Critical Impact
Any authenticated user can terminate, pause, or unpause other users' training tasks, disrupting long-running ML workloads and causing loss of compute state.

Affected Products

Determined AI Determined training platform
Generic task API handlers in master/internal/api_generic_tasks.go
Multi-user Determined cluster deployments

Discovery Timeline

2026-08-17 - CVE-2026-75109 published to NVD
2026-08-18 - Last updated in NVD database

Technical Details for CVE-2026-75109

Vulnerability Analysis

Determined exposes a set of generic task endpoints that manage workload lifecycle operations across the cluster. The kill, pause, and unpause handlers in api_generic_tasks.go accept a task identifier and dispatch the requested action to the task manager. The handlers authenticate the caller but omit the authorization check that binds the caller's identity to the target task's owner or workspace role. As a result, the server executes state-changing operations on any task ID the caller can enumerate or guess.

An attacker with a valid Determined account can iterate task identifiers and issue kill requests to terminate other users' training jobs. Pause and unpause requests further allow the attacker to stall workloads or resume them at unexpected times, corrupting scheduling assumptions. The impact is limited to task availability and minor integrity effects on task state; the flaw does not expose task data or credentials.

Root Cause

The root cause is a missing authorization check [CWE-862] in the generic task API layer. Determined's handler code invokes task lifecycle actions without evaluating whether the authenticated principal owns the task or holds the required workspace role. See the GitHub API source code and GitHub Issue #10270 for the affected code path.

Attack Vector

Exploitation requires network access to the Determined master API and valid credentials for any account on the cluster. The attacker sends authenticated HTTP requests to the generic task kill, pause, or unpause endpoints, supplying task identifiers belonging to other users. No user interaction or elevated privileges are required. Refer to the VulnCheck Security Advisory for additional exploitation context.

Detection Methods for CVE-2026-75109

Indicators of Compromise

Unexpected task terminations recorded in the Determined master audit log where the acting user does not match the task owner.
API request logs showing calls to generic task kill, pause, or unpause endpoints from user accounts that do not own the referenced task IDs.
User complaints about training jobs stopping without cause or restarting outside scheduled windows.

Detection Strategies

Correlate task state transitions with the authenticated principal on each request and alert when the caller differs from the task owner.
Baseline per-user rates of kill, pause, and unpause operations, then flag spikes or cross-user targeting patterns.
Ingest Determined master logs into the security data lake and build queries that join task ownership metadata with API access records.

Monitoring Recommendations

Enable verbose audit logging on the Determined master and forward logs to a centralized SIEM for retention and analysis.
Monitor authentication events for accounts that begin issuing task lifecycle operations at higher volumes than historical norms.
Track HTTP 200 responses to kill, pause, and unpause endpoints alongside the requesting user identity for anomaly review.

How to Mitigate CVE-2026-75109

Immediate Actions Required

Upgrade Determined to the fixed release once published by the vendor; track status in GitHub Issue #10270.
Restrict Determined master API access to trusted networks and known operator subnets while a patch is being rolled out.
Audit existing user accounts and disable or rotate credentials for accounts that no longer require cluster access.

Patch Information

Refer to the upstream Determined project repository for the authoritative fix commit and release notes. The VulnCheck advisory tracks vendor remediation status for this issue.

Workarounds

Segment Determined clusters so that untrusted or lower-trust users run on isolated deployments away from production ML workloads.
Place the Determined master API behind an authenticating reverse proxy that enforces additional per-endpoint access controls.
Reduce the number of users with active Determined credentials to only those with an operational need during the exposure window.

bash

# Configuration example
# Restrict Determined master API to trusted CIDR ranges at the network layer
# Example iptables rules on the master host
iptables -A INPUT -p tcp --dport 8080 -s 10.0.0.0/8 -j ACCEPT
iptables -A INPUT -p tcp --dport 8080 -j DROP