{"id":"CVE-2026-62943","aliases":["DEBIAN-CVE-2026-62943","EUVD-2026-83054","GHSA-pf45-7g54-65h5","UBUNTU-CVE-2026-62943"],"status":"published","title":"btrbk: SSH Command Filter Bypass in ssh_filter_btrbk.sh","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.","severity":{"version":"4.0","score":8.7,"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","level":"high","assessor":"cna","from":"cve"},"epss":{"day":"2026-11-12","score":0.00496,"percentile":0.43078,"model":"v2026.06.15"},"facts":{"in_kev":false,"known_exploited":false,"public_exploit":false,"fix_available":false},"cwes":["CWE-78"],"published":"2026-09-18T16:24:48Z","modified":"2026-11-12T17:26:06Z","affected":[{"source":"osv","ecosystem":"Debian:12","package":"btrbk","ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"}]}],"versions":["0.32.5-1","0.32.5-1.1","0.32.6-1","0.32.6-2"]},{"source":"osv","ecosystem":"Debian:13","package":"btrbk","ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"}]}],"versions":["0.32.6-2"]},{"source":"osv","ecosystem":"Debian:14","package":"btrbk","ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"}]}],"versions":["0.32.6-2"]},{"source":"osv","ecosystem":"Ubuntu:16.04:LTS","package":"btrbk","ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"}]}],"versions":["0.19.3-1","0.20.0-1","0.21.0-1","0.22.0-1","0.22.1-1","0.22.2-1"]},{"source":"osv","ecosystem":"Ubuntu:Pro:18.04:LTS","package":"btrbk","ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"}]}],"versions":["0.25.1-1","0.26.0-1","0.26.0-1ubuntu0.1~esm1"]},{"source":"osv","ecosystem":"Ubuntu:Pro:20.04:LTS","package":"btrbk","ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"}]}],"versions":["0.27.1-1","0.27.1-1ubuntu0.1~esm1"]},{"source":"osv","ecosystem":"Ubuntu:22.04:LTS","package":"btrbk","ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"}]}],"versions":["0.27.1-2","0.31.3-1"]},{"source":"osv","ecosystem":"Ubuntu:24.04:LTS","package":"btrbk","ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"}]}],"versions":["0.32.5-1"]},{"source":"osv","ecosystem":"Ubuntu:26.10","package":"btrbk","ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"}]}],"versions":["0.32.6-2"]},{"source":"osv","ecosystem":"Ubuntu:26.04:LTS","package":"btrbk","ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"}]}],"versions":["0.32.6-2"]}],"products":[{"vendor":"digint","product":"btrbk"}],"references":[{"url":"https://github.com/digint/btrbk/security/advisories/GHSA-pf45-7g54-65h5","tags":["x_refsource_CONFIRM","advisory","report"]},{"url":"https://github.com/digint/btrbk/commit/29ca3c093205395bdeb9dd98677ab4139c458aec","tags":["x_refsource_MISC","fix","report"]},{"url":"https://github.com/digint/btrbk/releases/tag/v0.32.7","tags":["x_refsource_MISC","web","report"]},{"url":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/62xxx/CVE-2026-62943.json","tags":["advisory"]},{"url":"https://nvd.nist.gov/vuln/detail/CVE-2026-62943","tags":["advisory"]},{"url":"https://security-tracker.debian.org/tracker/CVE-2026-62943","tags":["advisory"]},{"url":"https://ubuntu.com/security/CVE-2026-62943","tags":["report"]},{"url":"https://www.cve.org/CVERecord?id=CVE-2026-62943","tags":["report"]}],"sources":{"cve":[{"id":"CVE-2026-62943","title":"btrbk: SSH Command Filter Bypass in ssh_filter_btrbk.sh","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":"published","published":"2026-09-18T16:24:48.513Z","modified":"2026-09-21T20:50:09.611Z","cvss":[{"version":"4.0","score":8.7,"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","level":"high","assessor":"cna"}],"cwes":["CWE-78"],"updated_at":"2026-11-02T14:20:14.999906Z"}],"euvd":[{"id":"EUVD-2026-83054","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":"published","published":"2026-09-18T16:24:48Z","modified":"2026-09-21T20:50:09Z","cvss":[{"version":"4.0","score":8.7,"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","level":"high"}],"updated_at":"2026-11-02T17:28:04.224689Z"}],"nvd":[{"id":"CVE-2026-62943","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":"published","published":"2026-09-18T17:16:59.167Z","modified":"2026-09-24T21:25:27.05Z","cvss":[{"version":"4.0","score":8.7,"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/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X","level":"high","assessor":"secondary"}],"cwes":["CWE-78"],"updated_at":"2026-11-02T14:12:49.70655Z"}],"osv":[{"id":"CVE-2026-62943","title":"btrbk: SSH Command Filter Bypass in ssh_filter_btrbk.sh","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":"published","published":"2026-09-18T16:24:48.513Z","modified":"2026-10-28T02:30:37.07198196Z","cvss":[{"version":"4.0","score":8.7,"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","level":"high"}],"cwes":["CWE-78"],"updated_at":"2026-11-02T15:45:13.306117Z"},{"id":"DEBIAN-CVE-2026-62943","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":"published","published":"2026-09-18T17:16:59.167Z","modified":"2026-09-25T08:47:25.354551303Z","cvss":[{"version":"4.0","score":8.7,"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/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X","level":"high"}],"updated_at":"2026-11-02T15:45:57.932517Z"},{"id":"UBUNTU-CVE-2026-62943","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":"published","published":"2026-09-18T17:16:00Z","modified":"2026-11-12T17:26:06.789359483Z","cvss":[{"version":"4.0","score":8.7,"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","level":"high"}],"updated_at":"2026-11-12T18:06:16.272906Z"}]}}