CVE-2026-62943: CWE-78: Improper Neutralization of Special Elements used in an OS Command ('OS Command Injection') in digint btrbk
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.
AI Analysis
Technical Summary
btrbk versions 0.29.0 to 0.32.6 use ssh_filter_btrbk.sh to construct allow_stream_match with a start anchor but lack an end-of-string anchor for the complete command. This allows a user restricted through an authorized_keys forced command to append a trailing pipe and arbitrary commands after a valid btrbk command prefix, effectively bypassing the allowlist and executing arbitrary commands with the backup-target SSH account's privileges. Deployments not using ssh_filter_btrbk.sh in authorized_keys are not affected. The vulnerability is addressed in version 0.32.7.
Potential Impact
An attacker with access to an SSH account restricted by an authorized_keys forced command using ssh_filter_btrbk.sh can execute arbitrary OS commands with the privileges of the backup-target SSH account. This could lead to unauthorized command execution and potential compromise of the backup system.
Mitigation Recommendations
Upgrade btrbk to version 0.32.7 or later where this vulnerability is fixed. Deployments not using ssh_filter_btrbk.sh in authorized_keys are not affected and require no action related to this issue.
CVE-2026-62943: CWE-78: Improper Neutralization of Special Elements used in an OS Command ('OS Command Injection') in digint btrbk
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.
CVSS v4.0
Score 8.7high
Affected software
digint
btrbk
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Weaknesses
AI-Powered Analysis
Machine-generated threat intelligence
Technical Analysis
btrbk versions 0.29.0 to 0.32.6 use ssh_filter_btrbk.sh to construct allow_stream_match with a start anchor but lack an end-of-string anchor for the complete command. This allows a user restricted through an authorized_keys forced command to append a trailing pipe and arbitrary commands after a valid btrbk command prefix, effectively bypassing the allowlist and executing arbitrary commands with the backup-target SSH account's privileges. Deployments not using ssh_filter_btrbk.sh in authorized_keys are not affected. The vulnerability is addressed in version 0.32.7.
Potential Impact
An attacker with access to an SSH account restricted by an authorized_keys forced command using ssh_filter_btrbk.sh can execute arbitrary OS commands with the privileges of the backup-target SSH account. This could lead to unauthorized command execution and potential compromise of the backup system.
Mitigation Recommendations
Upgrade btrbk to version 0.32.7 or later where this vulnerability is fixed. Deployments not using ssh_filter_btrbk.sh in authorized_keys are not affected and require no action related to this issue.
Technical Details
- Data Version
- 5.2
- Assigner Short Name
- GitHub_M
- Date Reserved
- 2026-07-14T22:32:17.731Z
- Cvss Version
- 4.0
- State
- PUBLISHED
Threat ID: 6aad678855bf5e2cf53e1039
Added to database: 09/18/2026, 16:32:08 UTC
Last enriched: 09/18/2026, 16:46:41 UTC
Last updated: 09/18/2026, 22:12:51 UTC
Views: 6
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