btrbk: SSH Command Filter Bypass in ssh_filter_btrbk.sh

{
  "id": "88cf0e6a35e18ba20a0969997d810032620c4fc341a073e674b21b28a1824136",
  "url": "https://osv.dev/vulnerability/CVE-2026-62943",
  "method": "structured",
  "payload": {
    "kind": "advisory",
    "title": "btrbk: SSH Command Filter Bypass in ssh_filter_btrbk.sh",
    "summary": "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.",
    "evidence": "osv:CVE-2026-62943",
    "products": [],
    "severity": "high",
    "structured": {
      "id": "CVE-2026-62943",
      "aliases": [
        "CVE-2026-62943",
        "GHSA-pf45-7g54-65h5"
      ],
      "metrics": [
        {
          "type": "CVSS_V4",
          "score": "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"
        }
      ],
      "affected": [
        {
          "ranges": [
            {
              "repo": "https://github.com/digint/btrbk",
              "type": "GIT",
              "events": [
                {
                  "introduced": "b64ffbacf5a089df63429b6cd315974213674348"
                },
                {
                  "fixed": "b4676b841865763901712153281de4b1291cedc6"
                },
                {
                  "fixed": "29ca3c093205395bdeb9dd98677ab4139c458aec"
                }
              ],
              "database_specific": {
                "extracted_events": [
                  {
                    "range": [
                      {
                        "introduced": "0.29.0"
                      },
                      {
                        "fixed": "0.32.7"
                      }
                    ],
                    "source": "AFFECTED_FIELD",
                    "strategy": "StringRangeExpression"
                  },
                  {
                    "range": [
                      {
                        "fixed": "29ca3c093205395bdeb9dd98677ab4139c458aec"
                      }
                    ],
                    "source": "REFERENCES_COMMIT"
                  },
                  {
                    "range": [
                      {
                        "fixed": "b4676b841865763901712153281de4b1291cedc6"
                      }
                    ],
                    "source": "REFERENCES_TAG",
                    "original_tag": "v0.32.7"
                  }
                ]
              }
            }
          ],
          "versions": [
            "v0.32.6",
            "v0.32.5",
            "v0.32.4",
            "v0.32.3",
            "v0.32.2",
            "v0.32.1",
            "v0.32.0",
            "v0.31.3",
            "v0.31.2",
            "v0.31.1",
            "v0.31.0",
            "v0.30.0",
            "v0.29.1",
            "v0.29.0"
          ],
          "database_specific": {
            "source": "https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-62943.json"
          }
        }
      ],
      "modified": "2026-10-28T02:30:37.071981960Z",
      "provider": "osv",
      "references": [
        "https://github.com/digint/btrbk/releases/tag/v0.32.7",
        "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/62xxx/CVE-2026-62943.json",
        "https://github.com/digint/btrbk/security/advisories/GHSA-pf45-7g54-65h5",
        "https://nvd.nist.gov/vuln/detail/CVE-2026-62943",
        "https://github.com/digint/btrbk/commit/29ca3c093205395bdeb9dd98677ab4139c458aec"
      ],
      "provider_metadata": {
        "cwe_ids": [
          "CWE-78"
        ],
        "cna_assigner": "GitHub_M",
        "osv_generated_from": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/62xxx/CVE-2026-62943.json"
      }
    },
    "related_cves": [
      {
        "value": "CVE-2026-62943",
        "evidence": "/id"
      }
    ],
    "security_relevant": true,
    "severity_evidence": "/severity/0/score"
  },
  "source_id": "core-osv",
  "document_id": 504286,
  "published_at": "2026-09-18T16:24:48.513+00:00"
}