CVE-2026-62943
btrbk: SSH Command Filter Bypass in ssh_filter_btrbk.sh
- State
- Published
- Severity
- 8.7 High
- Published
- Sep 18, 2026
- Updated
- Sep 21, 2026
- Reserved
- Jul 14, 2026
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.
Scores
| CVSS | Score | Vector | Source |
|---|---|---|---|
| 4.0 | 8.7 High | 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 | GitHub_M |
Weaknesses
- CWE-78 Improper Neutralization of Special Elements used in an OS Command ('OS Command Injection')
Affected Products
| Product | Versions |
|---|---|
btrbkdigint |
|
References
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