CVE Catalog

CVE-2026-62943

HighCVSS 8.7
Published: Updated: Translated: NVD NIST

Exploitation Probability (EPSS)

Low risk
0.50%

40th percentile - higher than 40% of all known CVEs

Summary

In btrbk from 0.29.0 until 0.32.7, the ssh_filter_btrbk.sh script constructs allow_stream_match with a start anchor but no end-of-string anchor for the full command. A user restricted via an authorized_keys forced command can append a trailing pipe command after a valid btrbk prefix, bypassing the allowlist and executing arbitrary commands with the backup-target SSH account's privileges. This is fixed in version 0.32.7.

Risk Assessment

An SSH-restricted user can execute arbitrary commands on the backup target server, potentially leading to full account compromise or data modification/deletion. This affects deployments using ssh_filter_btrbk.sh in authorized_keys.

Recommendation

Upgrade btrbk to version 0.32.7 or later. Review authorized_keys configuration and consider additional command restrictions.

Related vulnerabilities

Original NVD description (English source)

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.

Vulnerability data from NVD (NIST) · CISA KEV · EPSS