How severe is CVE-2026-48786?

CVE-2026-48786 has a CVSS score of 6.5/10, rated MEDIUM. Review your exposure and patch according to your risk tolerance.

Which packages are affected by CVE-2026-48786?

CVE-2026-48786 affects the following packages: github.com/fleetdm/fleet/v4 (Go). Ecosystems affected: Go.

How do I fix CVE-2026-48786?

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.

How do I detect CVE-2026-48786 in my Go dependencies?

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.

How do I mitigate CVE-2026-48786 if there is no patch (or I can't update yet)?

Assume what was exposed is already known: rotate any credential, token or key that the affected component could return, restrict the endpoint to callers that genuinely need it, and strip sensitive fields from responses and error output at the boundary rather than relying on the client not to read them.

Is CVE-2026-48786 actively exploited in the wild?

No public exploit code has been indexed for CVE-2026-48786 yet. This does not mean the vulnerability cannot be exploited — absence of public exploits does not imply safety. Apply the recommended fix and use O3 Security to monitor your exposure.

What is the EPSS score for CVE-2026-48786?

CVE-2026-48786 has an EPSS (Exploit Prediction Scoring System) score of 0.4%, placing it in the 36th percentile of all CVEs. EPSS is maintained by FIRST.org and estimates the probability that a vulnerability will be exploited in the wild within the next 30 days. This score indicates relatively lower exploitation probability, though the CVSS severity should still guide your patching priority.

What type of vulnerability is CVE-2026-48786?

CVE-2026-48786 is classified as Information Exposure (CWE-200). This weakness type describe the underlying flaw category, which helps determine the potential impact and the right class of mitigation.

When was CVE-2026-48786 published, and has it been updated?

CVE-2026-48786 was published on August 26, 2026 and was last updated on September 29, 2026. Advisory data evolves as severity scores, affected ranges, and exploit intelligence are revised — always check the latest version of the advisory before acting.

🐹

🐹 Go

Not in CISA KEV

MEDIUM severity

CVE-2026-48786 — v4

MEDIUMFix: fleetdm/fleet@6a48147

CVE-2026-48786 is a medium-severity (CVSS 6.5) Information Exposure 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: Observer-class users can view team enroll secrets and credential-bearing configuration via target search endpoint

Also known asGHSA-88p2-jj8w-j8qgGO-2026-6220

Published

Aug 26, 2026

Updated

Sep 29, 2026

Affected

1 pkg

Patched

1 / 1

Exploits

None indexed

Exploitation data as of Sep 28, 2026 · OSV.dev, NVD, FIRST.org (EPSS)

Exploitation Status

No confirmed exploitation observed yet

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-2026-48786.

EPSS Exploitation Probability

via FIRST.org ↗

0.4%probability of exploitation in next 30 days

Lower Risk0.00%

Lower risk than most CVEs36th percentile — riskier than 36% of all scored CVEsHighest risk

Probability of exploitation in the next 30 days, from FIRST.org EPSS.

How urgent is this, really

CVE-2026-48786 by exploitation likelihood (EPSS) against impact (CVSS). Outside the shaded patch-first corner.

Where this sits among everything scored

Of 380,526 CVEs with a current EPSS score, this one falls in the < 10% band (highlighted). Counts from FIRST.org, log-scaled.

Real-World Exposure

1 pkg affected

🐹github.com/fleetdm/fleet/v4

Real-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

1 total 1 fixed

Ecosystem	Package	Vulnerable range	Fix
🐹Go	`github.com/fleetdm/fleet/v4`	all versions	4.87.0`go get github.com/fleetdm/fleet/v4@v4.87.0`

Detection & mitigation playbook

Open-source dependency

Detect
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 4.87.0 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
Assume what was exposed is already known: rotate any credential, token or key that the affected component could return, restrict the endpoint to callers that genuinely need it, and strip sensitive fields from responses and error output at the boundary rather than relying on the client not to read them.

Frequently Asked Questions

### 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, a