CVE-2026-48786
MEDIUMCVE-2026-48786 is a medium-severity (CVSS 6.5) vulnerability in github.com/fleetdm/fleet/v4. O3 Security confirms whether CVE-2026-48786 is actually reachable in your code before you act, and blocks exploitation at runtime until you patch.
Fleet: Observer-class users can view team enroll secrets and credential-bearing configuration via target search endpoint
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
The target search endpoint (POST /api/latest/fleet/targets) returned team enroll secrets and full team configuration, including credential-bearing agent options, to observer-class users. Other team-facing endpoints mask these fields for observers; the target search endpoint did not apply the same sanitization.
Impact
An authenticated user with Observer, Observer+, or Technician role (global or team-scoped) could retrieve unmasked team enroll secrets and team agent options by performing a target search against an observer-runnable query.
With a leaked team enroll secret, an attacker could enroll unauthorized hosts into the affected team. If the team's agent options contained credentials such as AWS secret access keys or proxy passwords, those values were also exposed.
Patches
- v4.87.0
Workarounds
If an immediate upgrade is not possible, administrators should:
- Rotate team enroll secrets for any team that may have been exposed
- Rotate any credentials stored in team agent options (AWS keys, proxy passwords, session tokens)
- Restrict Observer and Technician roles to fully trusted users until the patch is applied
Credits
Fleet thanks @fuzzztf for responsibly reporting this issue.
For more information
If there are any questions or comments about this advisory:
Send an email to [email protected] Join #fleet in osquery Slack
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| 🐹Go | github.com/fleetdm/fleet/v4 | all versions | 4.87.0 |
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 4.87.0 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2026-48786 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-2026-48786 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-2026-48786. 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-2026-48786 in your dependencies?
O3 detects CVE-2026-48786 across Go dependencies and uses function-level reachability to confirm whether the vulnerable code path is actually reachable — not just present. No false positives.