CVE-2026-26191

criticalpriority · track · 39EPSS 0.008 · 55 %ileDEEUUS

grimoire priorityP2 · Scheduled

Exploitable?

—

no known exploitation

Likely / severe?

0.77% (55th) EPSS

CVSS 9.8 · critical

Is it mine?

9 products

Check your exposure

Who says so?

5 sources

cnnvd · enisa_euvd · osv · cert_bund

EPSS · scored 2026-10-27

Fleet is open source device management software. Prior to version 4.81.0, a vulnerability in Fleet's software installer pipeline could allow a crafted software package to execute arbitrary commands as root (macOS/Linux) or SYSTEM (Windows) on managed endpoints when an uninstall is triggered. When a software package (.pkg, .deb, .rpm, .exe, or .msi) is uploaded to Fleet, metadata is extracted from the package binary and used to generate uninstall scripts. In affected versions, this metadata is not properly sanitized before being included in the generated scripts. A specially crafted package containing malicious values in its metadata fields could result in unintended command execution when the uninstall script runs on managed endpoints. Version 4.81.0 contains a patch. If an immediate upgrade is not possible, administrators should avoid uploading software packages obtained from untrusted or unverified sources. Additionally, administrators can manually inspect and edit auto-generated uninstall scripts before deployment.

cvss

Technical severity, 0–10. One row per scoring source.

9.8

010

base score 0–10 · higher = more severe · hover a vector to decode⚠ sources disagree · low–critical · 2.3–9.8

v3.19.8criticalCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:Hprimary · NVD / NIST USexploitability 3.9 · impact 5.9

v4.06mediumCVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:P/VC:N/VI:H/VA:N/SC:N/SI:N/SA:Nsecondary · ENISA EU

v4.06mediumCVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:P/VC:N/VI:H/VA:N/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:Xsecondary · security-advisories@github.com

v4.02.3lowCVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:P/VC:N/VI:H/VA:N/SC:N/SI:N/SA:N/E:U/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:Xsecondary · CVSS-BT (t0sche)

ssvc

A stakeholder decision — act, attend, or track — from exploitation and impact.

Trackcoordinatorcisa_ssvcUS

weaknesses

The CWE weakness classes this flaw belongs to.

CWE-78USCWE-78US

affected products (9)

Products and version ranges known to be affected.

Open Source Fleet <4.80.1all versionscert_bundDE
Open Source Fleet <4.81.0all versionscert_bundDE
Open Source Fleet <4.82.0all versionscert_bundDE
Open Source Fleet< 4.80.1cert_bundDE
Open Source Fleet< 4.81.0cert_bundDE
Open Source Fleet< 4.82.0cert_bundDE
fleetdm Fleet≤ < 4.81.1enisa_euvdEU
fleetdm fleet< 4.81.0nvdUScpe:2.3:a:fleetdm:fleet:*:*:*:*:*:*:*:*
Go github.com/fleetdm/fleet/v4< 4.81.1osvUSpkg:golang/github.com/fleetdm/fleet/v4

advisories (3)

Vendor and ecosystem advisories describing this.

WID-SEC-W-2026-1553Fleet: Mehrere SchwachstellenDeutsch2026-05-14csaf · cert_bundDE
Ein entfernter, anonymer Angreifer kann mehrere Schwachstellen in Fleet ausnutzen, um Sicherheitsmaßnahmen zu umgehen, Daten zu manipulieren oder offenzulegen oder einen Denial-of-Service-Zustand herbeizuführen.
GHSA-9vcr-g537-3w5vFleet vulnerable to OS command injection in software packages2026-05-14ghsa · osvUS
### Summary A vulnerability in Fleet's software installer pipeline could allow a crafted software package to execute arbitrary commands as root (macOS/Linux) or SYSTEM (Windows) on managed endpoints when an uninstall is triggered. ### Impact When a software package (.pkg, .deb, .rpm, .exe, or .msi) is uploaded to Fleet, metadata is extracted from the package binary and used to generate uninstall scripts. In affected versions, this metadata is not properly sanitized before being included in the generated scripts. A specially crafted package containing malicious values in its metadata fields could result in unintended command execution when the uninstall script runs on managed endpoints. ### Workarounds If an immediate upgrade is not possible, administrators should avoid uploading software packages obtained from untrusted or unverified sources. Additionally, administrators can manually inspect and edit auto-generated uninstall scripts before deployment. ### For more information If you have any questions or comments about this advisory: Email us at [[security@fleetdm.com](mailto:security@fleetdm.com)](mailto:security@fleetdm.com) Join #fleet in [[osquery Slack](https://join.slack.com/t/osquery/shared_invite/zt-h29zm0gk-s2DBtGUTW4CFel0f0IjTEw)](https://join.slack.com/t/osquery/shared_invite/zt-h29zm0gk-s2DBtGUTW4CFel0f0IjTEw) ### Credits We thank @secfox-ai for responsibly reporting this issue.
GO-2026-5301Fleet vulnerable to OS command injection in software packages in github.com/fleetdm/fleet2026-06-25vendor · osvUS
Fleet vulnerable to OS command injection in software packages in github.com/fleetdm/fleet

also known as (5)

Other names and identifiers for this entity.

sources

Which sources assert this record, and when.

cnnvd enisa_euvd osv cert_bund nvd NVD CVE.org MITRE

published 2026-05-14modified 2026-10-26

references (7)

External citations — patches, advisories, analysis.

scry

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