CVE-2026-25963
Fleet: Authorization Bypass in certificate template batch deletion for team administrators
EPSS Exploitation Probability
EPSS (Exploit Prediction Scoring System) is a daily probability model maintained by FIRST.org. It estimates the likelihood a CVE will be exploited in production environments within the next 30 days, derived from real-world threat intelligence signals.
Blast Radius
github.com/fleetdm/fleet/v4Real-time download stats are indexed for npm and PyPI packages. This vulnerability affects Go packages — download data is not available via public APIs for these ecosystems.
Description
Fleet is open source device management software. In versions prior to 4.80.1, a broken authorization check in Fleet’s certificate template deletion API could allow a team administrator to delete certificate templates belonging to other teams within the same Fleet instance. Fleet supports certificate templates that are scoped to individual teams. In affected versions, the batch deletion endpoint validated authorization using a user-supplied team identifier but did not verify that the certificate template IDs being deleted actually belonged to that team. As a result, 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. This issue does not allow privilege escalation, access to sensitive data, or compromise of Fleet’s control plane. Impact is limited to integrity and availability of certificate templates across teams. Version 4.80.1 patches the issue. If an immediate upgrade is not possible, administrators should restrict access to certificate template management to trusted users and avoid delegating team administrator permissions where not strictly required.
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| 🐹Go | github.com/fleetdm/fleet/v4 | all versions | 4.80.1 |
Detection & mitigation playbook
Open-source dependencyDetect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for github.com/fleetdm/fleet/v4. O3's reachability analysis confirms whether the vulnerable code path is actually invoked in your application, so you act on real exposure instead of every transitive match.
Fix
Update github.com/fleetdm/fleet/v4 to 4.80.1 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2026-25963 is resolved across your whole dependency graph.
Workarounds
If you can't upgrade right away: gate or disable the affected feature, validate untrusted input at the boundary, and avoid passing attacker-controlled data into the vulnerable path. O3's runtime protection blocks exploitation in production as an interim safeguard until the upgrade lands.
How O3 protects you
O3 pinpoints whether CVE-2026-25963 is reachable in your code and exactly where to fix it, then blocks exploitation in production at runtime until the patched version is deployed.
Tailored to CVE-2026-25963. Runtime protection reduces exposure until a permanent patch is applied and verified — it complements patching, it doesn't replace it.
Frequently Asked Questions
Is CVE-2026-25963 in your dependencies?
O3 detects CVE-2026-25963 across Go dependencies and uses function-level reachability to confirm whether the vulnerable code path is actually reachable — not just present. No false positives.