What’s Vulnerable › Vulnerabilities

CVE-2026-62943: btrbk: SSH Command Filter Bypass in ssh_filter_btrbk.sh

• Severity: high (CVSS 8.7 v4.0)
• Exploited in the wild: not listed in CISA KEV
• EPSS: 0.5% probability of exploitation in the next 30 days
• Public exploit or detection template: none known
• Published: 2026-09-18 · updated 2026-09-24
• Weakness: CWE-78

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.

Affected products

• digint btrbk: from 0.29.0, < 0.32.7

References

• https://github.com/digint/btrbk/commit/29ca3c093205395bdeb9dd98677ab4139c458aec
• https://github.com/digint/btrbk/releases/tag/v0.32.7
• https://github.com/digint/btrbk/security/advisories/GHSA-pf45-7g54-65h5

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