GHSA-9q28-ghcr-c4x3: PraisonAI's symlink-extraction bypass of `_safe_extractall` writes outside `dest_dir`
SummaryThe `_safe_extractall` helper that all `recipe pull`, `recipe publish`, and `recipe unpack` flows route through validates each archive member's `name` for absolute paths, `..` segments, and resolved-path escape — but does **not** validate `member.linkname`, does not reject symlink/hardlink members, and calls `tar.extractall(dest_dir)` without `filter="data"`. A bundle that contains a symlink with a name
inside `dest_dir` but a `linkname` pointing outside it, followed by a regular file whose path traverses *through* the just-created symlink, escapes `dest_dir` and lets the attacker write arbitrary content to an attacker-chosen location on the victim's filesystem.Affected pathsEvery code path that calls `_safe_extractall` is exposed:| Caller | File:line |
|---|---|
| `praisonai recipe unpack` | `src/praisonai/praisonai/cli/features/recipe.py:1175` (introduced as the fix for GHSA-99g3-w8gr-x37c) |
| `LocalRegistry.unpack` (recipe pull) | `src/praisonai/praisonai/recipe/registry.py:413` |
| Registry archive validation (publish) | `src/praisonai/praisonai/recipe/registry.py:808` |Root cause`recipe/registry.py:131-178`:Three gaps:The loop checks only `member.name`. `member.linkname` (the symlink / hardlink target) is not inspected.`member.issym()` and `member.islnk()` are not used to refuse link members at all.`tar.extractall(dest_dir)` runs without `filter="data"`. On Python ≤ 3.13 the default is `fully_trusted` (with a DeprecationWarning on 3.12+), which permits symlinks pointing outside `dest_dir`.When the archive is extracted in member order, the symlink lands first, and any subsequent member whose path traverses through that symlink follows it to the attacker's chosen location.ReproductionTested in a disposable container against `praisonai==4.6.35` (`pip install praisonai`, no other modifications).`make_bundle.py`:`direct_test.py`:Run:Observed output:`/tmp/PWNED/owned.txt` exists after the call returns, written outside the destination directory the helper was asked to extract into.ImpactArbitrary file write with attacker-controlled content to an attacker-chosen path, on every host that processes a malicious `.praison` bundle through any of the three callers above.Realistic exploitation paths:A user runs `praisonai recipe unpack ./<malicious>.praison` after obtaining the bundle from a shared registry, a tutorial link, or
direct messaging.A user runs `praisonai recipe pull <name>` against a malicious or compromised registry.A registry server processes an uploaded `.praison` bundle (the publish path is reachable over the network if the server is exposed. per GHSA-r9x3-wx45-2v7f and GHSA-2xgv-5cv2-47vv).Where the agent process runs as a regular user, the attacker can overwrite shell config (`.bashrc`, `.zshrc`, `.profile`), SSH `authorized_keys`, cron entries, or project files in adjacent directories. Where the process runs as root (registry-server deployments and some `sudo`-launched workflows), the attacker controls arbitrary system files.This re-opens the `recipe pull`, `recipe publish`, and `recipe unpack` paths that GHSA-99g3-w8gr-x37c, GHSA-4rx4-4r3x-6534, GHSA-r9x3-wx45-2v7f, and GHSA-4ph2-f6pf-79wv were each intended to close.Suggested remediationSingle-line fix at `recipe/registry.py:178`:`filter="data"` (introduced in Python 3.12; available as a backport on 3.8+ via the official PEP 706 reference implementation) refuses
symlinks, hardlinks, device nodes, and absolute or escaping link targets, it is the canonical Python defense against this class.
If you also support older Python, add an explicit guard inside the existing per-member loop before `tar.extractall`:Affected versions`praisonai >= 2.7.2` through current `4.6.35` (the helper exists at least back to the earliest path-traversal patch chain referenced in
GHSA-99g3-w8gr-x37c). All releases that route extraction through `_safe_extractall` are exposed.DisclosureReported privately via the project's GHSA workflow at
https://github.com/MervinPraison/PraisonAI/security/advisories/new-- Dhiral Vyas
CVSS v4.0: 8.7
CVSS v3.1: 7.5