CVE-2026-26191

CRITICALNVD 9.89.8—
EchelonGraph scoreMEDIUM confidence

This critical-severity CVE scores 9.8 under NVD CVSS v3. EPSS exploit probability: 0.8%, top 49% of all CVEs by exploit prediction. GitHub Security Advisory data not yet ingested — confidence will rise once GHSA publishes (typical lag: hours to days for open-source ecosystem CVEs; never for infrastructure-only CVEs).

Triggered by: NVD CVSS baseline
Sources: epss, nvd
9.8
EchelonGraph verdictPlan a fixSerious severity, but no confirmed exploitation yet.
  • High severity, but no confirmed exploitation yet
CISA-KEV: Not listedEPSS: 1%CVSS: 9.8Exploit: NoneExposed: 0

No vendor fix yet — apply a workaround or compensating control (WAF / firewall / segmentation) and watch for a patch.

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 v3
9.8
EG Score
9.8(medium)
EPSS
51.4%
KEV
Not listed

Published

May 14, 2026

Last Modified

May 18, 2026

Advisory Details (2)

Auto-updated Jun 21, 2026
Patch available. Sources: github, github_release.
github Patch Available

OS command injection in software packages · Advisory · fleetdm/fleet · GitHub

https://github.com/fleetdm/fleet/security/advisories/GHSA-9vcr-g537-3w5v
github_release Patch Available

fleet-v4.81.1

Patch available: fleetdm/fleet fleet-v4.81.1

https://github.com/fleetdm/fleet/releases/tag/fleet-v4.81.1

Vendor Advisories for CVE-2026-26191(1)

These vendors published their own advisory mentioning this CVE — often with vendor-specific remediation steps + affected product lists not in NVD.

Affected Packages

(1 across 1 ecosystem)
Go(1)
PackageVulnerable rangeFixed inDependents
github.com/fleetdm/fleet/v4—4.81.1—

Weakness Classification(1)

MITRE Common Weakness Enumeration — the root-cause categories this CVE belongs to.

Data Freshness Timeline

(refreshed 9× in last 7d / 82× in last 30d)

Each row is a source pipeline that fetched or updated this CVE on that date, with what changed. For example, "NVD update" means NVD published or revised its analysis for this CVE; "MITRE cvelistV5" means we ingested or refreshed it from the CNA feed. Most recent first.

Showing the most recent 100 of 209 total refreshes for this CVE.

  1. 2026-07-11 08:27 UTCEPSS rescore
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  1. 2026-06-27 22:37 UTCEG score recompute
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Frequently asked(5)

What is CVE-2026-26191?
CVE-2026-26191 is a critical vulnerability published on May 14, 2026. 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…
When was CVE-2026-26191 disclosed?
CVE-2026-26191 was first published in the National Vulnerability Database on May 14, 2026, with the most recent update on May 18, 2026. EchelonGraph re-ingests CVE updates from NVD on a 2-hour cycle, so this page reflects the latest published state.
Is CVE-2026-26191 actively exploited?
CVE-2026-26191 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 51.4% percentile likelihood of exploitation in the next 30 days — higher percentiles indicate greater predicted risk.
What is the CVSS score of CVE-2026-26191?
CVE-2026-26191 has a CVSS v3 base score of 9.8 (NVD).
How do I remediate CVE-2026-26191?
Patch to the fixed version published by the affected vendor. Where vendor advisories exist for CVE-2026-26191, EchelonGraph cross-links them in the Vendor Advisories panel below — those typically contain the canonical remediation steps, fixed version numbers, and any vendor-specific mitigations.

Dependency Blast Radius

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