CVE-2026-23999: Fleet Device Lock PIN Can Be Vulnerability

MODERATE
Advisory Identifier: GHSA-ppwx-5jq7-px2w
CWE-330
Published
Advisory Summary

CVE-2026-23999 is a MODERATE device lock pin can be vulnerability (CWE-330: Use of Insufficiently Random Values) affecting Fleet libraries in the Go ecosystem. The issue involves device lock pin can be predicted if lock time is known. Remediation is available by upgrading affected packages to version 4.80.1.

CVE-2026-23999 at a Glance

CVE Identifier CVE-2026-23999
GHSA Identifier GHSA-ppwx-5jq7-px2w
Severity MODERATE
CVSS v3.1 Base Score N/A
CWE Classification CWE-330: Use of Insufficiently Random Values
Affected Product Fleet
Package Ecosystem Go
Published Date
Last Updated

How to Fix CVE-2026-23999

To remediate this vulnerability, upgrade all affected Fleet dependencies to a patched release. Both direct and transitive dependencies should be checked, as frameworks or security libraries may pull in vulnerable versions transitively.

github.com/fleetdm/fleet/v4 fixed: 4.80.1
Upgrade github.com/fleetdm/fleet/v4 to 4.80.1
Verify Direct and Transitive Dependencies

Run the following command in your project directory to verify that all resolved dependencies use the patched release:

inspect dependencies for github.com/fleetdm/fleet/v4

How to Check if You Are Affected

To determine whether your application is affected by CVE-2026-23999, inspect your project dependencies for Fleet:

inspect dependencies for github.com/fleetdm/fleet/v4

Analyze the terminal output to locate any version of Fleet in your dependency tree. If any resolved version matches the vulnerable ranges listed in the table below (for example, versions earlier than 4.80.1), your application is affected.

Note: Verify declared build manifests and deployed runtime container environments.

Technical Details

Vulnerability Mechanism & Technical Analysis

This vulnerability is classified under CWE-330: Use of Insufficiently Random Values, where the product uses insufficiently random numbers or values in a security context that depends on unpredictable numbers. In Fleet, software state validation or input boundaries are circumvented during processing. Review the official source advisory statement below for specific affected components, classes, and reproduction details.

Source Advisory Statement

### Summary Fleet generated device lock and wipe PINs using a predictable algorithm based solely on the current Unix timestamp. Because no secret key or additional entropy was used, the resulting PIN could potentially be derived if the approximate time the device was locked is known. ### Impact Fleet’s device lock and wipe commands generate a 6-digit PIN that is displayed to administrators for unlocking a device. In affected versions, this PIN was deterministically derived from the current timestamp. An attacker with physical possession of a locked device and knowledge of the approximate time the lock command was issued could theoretically predict the correct PIN within a limited search window. However, successful exploitation is constrained by multiple factors: - Physical access to the device is required. - The approximate lock time must be known. - The operating system enforces rate limiting on PIN entry attempts. - Attempts would need to be spread over multiple days. - Device wipe operations would typically complete before sufficient attempts could be made. As a result, this issue does not allow remote exploitation, fleet-wide compromise, or bypass of Fleet authentication controls. ### Workarounds There are no known workarounds for this issue. Customers should upgrade to a patched version. ### For more information If there are any questions or comments about this advisory: Email Fleet at [security@fleetdm.com](mailto:security@fleetdm.com) Join #fleet in [osquery Slack](https://join.slack.com/t/osquery/shared_invite/zt-h29zm0gk-s2DBtGUTW4CFel0f0IjTEw) ### Credits Fleet thanks @secfox-ai for responsibly reporting this issue.

CVE-2026-23999 Affected Fleet Versions

1 component(s)
Fixed Versions:
4.80.1
Product / Package Ecosystem Affected Versions Fixed Version
github.com/fleetdm/fleet/v4
Go
< 4.80.1
4.80.1

References

Frequently Asked Questions

What is CVE-2026-23999?
CVE-2026-23999 is a security vulnerability in Fleet involving Device lock PIN can be predicted if lock time is known under CWE-330: Use of Insufficiently Random Values.
Which Fleet versions are affected?
Affected versions include releases prior to 4.80.1 across affected packages: github.com/fleetdm/fleet/v4.
What version fixes CVE-2026-23999?
Upgrading to 4.80.1 (or the latest patched release for your respective branch) resolves the vulnerability.
Is github.com/fleetdm/fleet/v4 affected?
Yes, github.com/fleetdm/fleet/v4 is affected in releases prior to 4.80.1. Upgrade your dependency to 4.80.1 or later.
What CWE is associated with CVE-2026-23999?
CVE-2026-23999 is classified under CWE-330: Use of Insufficiently Random Values (The product uses insufficiently random numbers or values in a security context that depends on unpredictable numbers.).
How can I check Go dependencies for CVE-2026-23999?
Run the dependency tree command: 'inspect dependencies for github.com/fleetdm/fleet/v4'. This command lists direct and transitive dependencies in your build configuration so you can verify if a vulnerable version is resolved.
Machine-readable OSV JSON OSV v1.5 Schema
Normalized schema output
{
  "schema_version" : "1.4.0",
  "id" : "GHSA-ppwx-5jq7-px2w",
  "modified" : "2026-02-26T19:35:29Z",
  "published" : "2026-02-26T19:35:29Z",
  "aliases" : [ "CVE-2026-23999" ],
  "summary" : "Fleet: Device lock PIN can be predicted if lock time is known",
  "details" : "### Summary\n\nFleet generated device lock and wipe PINs using a predictable algorithm based solely on the current Unix timestamp. Because no secret key or additional entropy was used, the resulting PIN could potentially be derived if the approximate time the device was locked is known.\n\n### Impact\n\nFleet’s device lock and wipe commands generate a 6-digit PIN that is displayed to administrators for unlocking a device. In affected versions, this PIN was deterministically derived from the current timestamp.\n\nAn attacker with physical possession of a locked device and knowledge of the approximate time the lock command was issued could theoretically predict the correct PIN within a limited search window.\n\nHowever, successful exploitation is constrained by multiple factors:\n- Physical access to the device is required.\n- The approximate lock time must be known.\n- The operating system enforces rate limiting on PIN entry attempts.\n- Attempts would need to be spread over multiple days.\n- Device wipe operations would typically complete before sufficient attempts could be made.\n\nAs a result, this issue does not allow remote exploitation, fleet-wide compromise, or bypass of Fleet authentication controls.\n\n### Workarounds\n\nThere are no known workarounds for this issue. Customers should upgrade to a patched version.\n\n### For more information\n\nIf there are any questions or comments about this advisory:\n\nEmail Fleet at [security@fleetdm.com](mailto:security@fleetdm.com)\nJoin #fleet in [osquery Slack](https://join.slack.com/t/osquery/shared_invite/zt-h29zm0gk-s2DBtGUTW4CFel0f0IjTEw)\n\n### Credits\n\nFleet thanks @secfox-ai for responsibly reporting this issue.",
  "severity" : [ {
    "type" : "CVSS_V4",
    "score" : "CVSS:4.0/AV:P/AC:H/AT:P/PR:N/UI:N/VC:N/VI:H/VA:N/SC:N/SI:N/SA:N"
  } ],
  "affected" : [ {
    "package" : {
      "ecosystem" : "Go",
      "name" : "github.com/fleetdm/fleet/v4"
    },
    "ranges" : [ {
      "type" : "ECOSYSTEM",
      "events" : [ {
        "introduced" : "0"
      }, {
        "fixed" : "4.80.1"
      } ]
    } ]
  } ],
  "references" : [ {
    "type" : "WEB",
    "url" : "https://github.com/fleetdm/fleet/security/advisories/GHSA-ppwx-5jq7-px2w"
  }, {
    "type" : "ADVISORY",
    "url" : "https://nvd.nist.gov/vuln/detail/CVE-2026-23999"
  }, {
    "type" : "WEB",
    "url" : "https://github.com/fleetdm/fleet/commit/05ca0693621e6671fb95dfc5437b9f9ee6dd7047"
  }, {
    "type" : "PACKAGE",
    "url" : "https://github.com/fleetdm/fleet"
  } ],
  "database_specific" : {
    "cwe_ids" : [ "CWE-330" ],
    "severity" : "MODERATE",
    "github_reviewed" : true,
    "github_reviewed_at" : "2026-02-26T19:35:29Z",
    "nvd_published_at" : "2026-02-26T03:16:04Z"
  }
}