CVE-2026-62943
Publication date 21 September 2026
Last updated 21 September 2026
Ubuntu priority
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.
Status
| Package | Ubuntu Release | Status |
|---|---|---|
| btrbk | 26.04 LTS resolute |
Needs evaluation
|
| 24.04 LTS noble |
Needs evaluation
|
|
| 22.04 LTS jammy |
Needs evaluation
|
|
| 20.04 LTS focal |
Needs evaluation
|
|
| 18.04 LTS bionic |
Needs evaluation
|
|
| 16.04 LTS xenial |
Needs evaluation
|
Severity score breakdown
CVSS version: CVSS v4.0
Base score
8.7 · High
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
References
Other references
- https://www.cve.org/CVERecord?id=CVE-2026-62943
- https://github.com/digint/btrbk/security/advisories/GHSA-pf45-7g54-65h5
- https://github.com/digint/btrbk/commit/29ca3c093205395bdeb9dd98677ab4139c458aec (v0.32.7)
- https://github.com/digint/btrbk/commit/29ca3c093205395bdeb9dd98677ab4139c458aec
- https://github.com/digint/btrbk/releases/tag/v0.32.7