CVE-2026-25963 — v4
Fix: fleetdm/fleet@d27d036CVE-2026-25963 is a CWE-863 vulnerability in github.com/fleetdm/fleet/v4. A fix is available for github.com/fleetdm/fleet/v4 — see the affected versions and patch details below.
Fleet: Authorization Bypass in certificate template batch deletion for team administrators
Exploitation Status
No confirmed exploitation observed yet
- CISA assesses this as automatable — exploitation doesn’t require manual, per-target effort, which raises the odds of mass scanning and opportunistic attacks.
- CISA’s own triage has not observed active exploitation or public proof-of-concept code for this CVE as of its last assessment.
Exploitation and automatability from CISA’s SSVC triage for CVE-2026-25963.
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.
Real-World Exposure
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
Summary
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.
Impact
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.
Patches
- v4.80.1
Workarounds
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.
For more information
If there are any questions or comments about this advisory:
Email Fleet at [email protected]
Join #fleet in osquery Slack
Credits
Fleet thanks @secfox-ai for responsibly reporting this issue.
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| 🐹Go | github.com/fleetdm/fleet/v4 | all versions | 4.80.1go get github.com/fleetdm/fleet/v4@v4.80.1 |
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, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.
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 Security's impact-aware SCA analyses which vulnerable code paths your application actually calls, so a match like CVE-2026-25963 can be triaged on real exposure rather than presence alone.
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 Security finds CVE-2026-25963 across Go dependencies, including transitive ones, and its impact-aware SCA ranks findings by whether your code actually calls the vulnerable path.