Description
btrbk is a tool for creating snapshots and remote backups of Btrfs subvolumes. From 0.29.0 until 0.32.7, btrbk's ssh_filter_btrbk.sh constructs allow_stream_match with a start anchor but without an end-of-string anchor for the complete command. A user restricted through an authorized_keys forced command can append a trailing pipe command after a valid btrbk command prefix, bypassing the allowlist and executing arbitrary commands with the privileges of the backup-target SSH account. Deployments that do not use ssh_filter_btrbk.sh in authorized_keys are not affected. This issue is fixed in version 0.32.7.
Published: 2026-09-18
Score: 8.7 High
EPSS: n/a
KEV: No
Impact: n/a
Action: n/a
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Remediation

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History

Fri, 18 Sep 2026 16:30:00 +0000

Type Values Removed Values Added
Description btrbk is a tool for creating snapshots and remote backups of Btrfs subvolumes. From 0.29.0 until 0.32.7, btrbk's ssh_filter_btrbk.sh constructs allow_stream_match with a start anchor but without an end-of-string anchor for the complete command. A user restricted through an authorized_keys forced command can append a trailing pipe command after a valid btrbk command prefix, bypassing the allowlist and executing arbitrary commands with the privileges of the backup-target SSH account. Deployments that do not use ssh_filter_btrbk.sh in authorized_keys are not affected. This issue is fixed in version 0.32.7.
Title btrbk: SSH Command Filter Bypass in ssh_filter_btrbk.sh
Weaknesses CWE-78
References
Metrics cvssV4_0

{'score': 8.7, 'vector': 'CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N'}

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cve-icon MITRE

Status: PUBLISHED

Assigner: GitHub_M

Published:

Updated: 2026-09-18T16:24:48.513Z

Reserved: 2026-07-14T22:32:17.731Z

Link: CVE-2026-62943

cve-icon Vulnrichment

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cve-icon NVD

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cve-icon Redhat

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cve-icon OpenCVE Enrichment

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Weaknesses
  • CWE-78

    Improper Neutralization of Special Elements used in an OS Command ('OS Command Injection')