CVE-2026-32241Network attack vector

Root command execution via backend-data shell injection

Published Mar 27, 2026 · Updated Mar 27, 2026

Command injection in flannel-io Flannel before 0.28.2 allows remote authenticated users to execute root commands across cluster nodes. SubnetAddCommand and SubnetRemoveCommand unmarshal the flannel.alpha.coreos.com/backend-data Node annotation and pipe its contents to a shell command without validation. Exploitation requires permission to set Kubernetes Node annotations and use of the experimental Extension backend; vxlan and wireguard are unaffected.

CVSS severity7.5
High
EPSS probability2.71%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Command injection in flannel-io Flannel before 0.28.2 allows remote authenticated users to execute root commands across cluster nodes. SubnetAddCommand and SubnetRemoveCommand unmarshal the flannel.alpha.coreos.com/backend-data Node annotation and pipe its contents to a shell command without validation. Exploitation requires permission to set Kubernetes Node annotations and use of the experimental Extension backend; vxlan and wireguard are unaffected.

The record

CVE
CVE-2026-32241
Published
Mar 27, 2026
Updated
Mar 27, 2026
Vendor
flannel-io
Product
flannel
Classifications
CWE-77, T1059.004
Attack vector
network
Privileges
authenticated

Timeline

How it unfolded

  1. Mar 27, 2026CVE publishedPublication date reported by the CVE source.
  2. Mar 27, 2026Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=< 0.28.2

What conditions does exploitation require?

Attack vectornetwork
Required privilegesauthenticated

What is affected?

flannel-io · flannelversion=< 0.28.2

Published CVSS scores

7.5GitHub, Inc.CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:H
8.8NIST NVDCVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

Daily unique IPsNo honeypot observations are available for this CVE in the selected window.

No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-77Improper Neutralization of Special Elements used in a Command ('Command Injection')
T1059.004Command and Scripting Interpreter: Unix Shell

Public exploit references

No public exploit references are available in this record.

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Technologies

Your stack

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Your stack

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