CVE-2026-25963 Overview
Fleet is open source device management software. A broken authorization check vulnerability has been identified in Fleet's certificate template deletion API that could allow a team administrator to delete certificate templates belonging to other teams within the same Fleet instance. This authorization bypass issue affects versions prior to 4.80.1.
Critical Impact
A team administrator could delete certificate templates associated with other teams, potentially disrupting certificate-based workflows such as device enrollment, Wi-Fi authentication, VPN access, or other certificate-dependent configurations for the affected teams.
Affected Products
- Fleet Device Management Software versions prior to 4.80.1
Discovery Timeline
- 2026-02-26 - CVE-2026-25963 published to NVD
- 2026-02-26 - Last updated in NVD database
Technical Details for CVE-2026-25963
Vulnerability Analysis
This vulnerability represents a Broken Access Control issue (CWE-863: Incorrect Authorization) in Fleet's certificate template management functionality. Fleet supports certificate templates that are scoped to individual teams, providing logical separation of certificate management across different organizational units.
The core issue lies in the batch deletion endpoint's authorization validation mechanism. While the endpoint validates authorization using a user-supplied team identifier, it fails to verify that the certificate template IDs being deleted actually belong to that team. This architectural oversight creates an authorization bypass condition where a team administrator can manipulate API requests to delete certificate templates outside their authorized scope.
The impact is limited to integrity and availability of certificate templates across teams. This issue does not allow privilege escalation, access to sensitive data, or compromise of Fleet's control plane.
Root Cause
The root cause is an improper authorization verification in Fleet's batch certificate template deletion API endpoint. The authorization logic trusts the user-supplied team identifier without performing a secondary validation to confirm that the specified certificate template IDs are associated with the claimed team. This represents a classic Insecure Direct Object Reference (IDOR) pattern combined with broken access control.
Attack Vector
The vulnerability is exploitable over the network and requires high privileges (team administrator access). An authenticated team administrator could craft API requests to the batch deletion endpoint, specifying their own team identifier for authorization purposes while including certificate template IDs belonging to other teams in the deletion payload.
The attack mechanism involves:
- An attacker with team administrator privileges authenticates to the Fleet instance
- The attacker identifies or enumerates certificate template IDs from other teams
- The attacker crafts a batch deletion request using their own team ID for authorization but targeting template IDs from other teams
- The flawed authorization check permits the deletion, affecting other teams' certificate workflows
Detection Methods for CVE-2026-25963
Indicators of Compromise
- Unexpected deletion of certificate templates that were not initiated by authorized team administrators
- Audit log entries showing certificate template deletions where the acting user's team does not match the team owning the deleted template
- Reports from team administrators about missing certificate templates
- Disruption in certificate-based workflows such as device enrollment failures, Wi-Fi authentication issues, or VPN access problems
Detection Strategies
- Review Fleet audit logs for certificate template deletion operations, correlating the acting user's team membership with the templates being deleted
- Implement alerting for bulk certificate template deletion operations
- Monitor for API calls to the certificate template batch deletion endpoint with anomalous patterns
- Cross-reference user session data with certificate template ownership during deletion requests
Monitoring Recommendations
- Enable verbose logging for certificate template management API endpoints
- Configure alerts for any certificate template deletions performed by users outside the template's associated team
- Implement regular audits of certificate template inventory across teams
- Monitor for unusual patterns in administrative API usage
How to Mitigate CVE-2026-25963
Immediate Actions Required
- Upgrade Fleet to version 4.80.1 or later immediately
- Audit recent certificate template deletions to identify any unauthorized cross-team deletions
- Review team administrator permissions and restrict access to certificate template management to trusted users only
- Avoid delegating team administrator permissions where not strictly required
Patch Information
Fleet version 4.80.1 addresses this vulnerability by implementing proper authorization checks that verify certificate template IDs belong to the authorized team before permitting deletion. Organizations should upgrade to this version or later to remediate the issue. For detailed information, refer to the GitHub Security Advisory.
Workarounds
- Restrict access to certificate template management functionality to only highly trusted administrators until the patch can be applied
- Implement additional network-level access controls to limit API access to authorized personnel
- Regularly backup certificate template configurations to enable rapid recovery if unauthorized deletions occur
- Monitor and alert on all certificate template deletion operations as an interim detective control
# Upgrade Fleet to patched version
# Using Fleet's recommended upgrade procedure
fleet prepare db
fleet serve --upgrade
# Verify version after upgrade
fleet version
# Expected output: fleet version 4.80.1 or later
Disclaimer: This content was generated using AI. While we strive for accuracy, please verify critical information with official sources.
