CVE-2026-22871
EPSS 0.24%GuardDog Path Traversal Vulnerability Leads to Arbitrary File Overwrite and RCE
Description
## Summary A **path traversal vulnerability** exists in GuardDog's `safe_extract()` function that allows malicious PyPI packages to write arbitrary files outside the intended extraction directory, leading to **Arbitrary File Overwrite** and **Remote Code Execution** on systems running GuardDog. **CWE:** CWE-22 (Improper Limitation of a Pathname to a Restricted Directory) ## Details ### Vulnerable Code **File:** `guarddog/utils/archives.py` ```python elif zipfile.is_zipfile(source_archive): with zipfile.ZipFile(source_archive, "r") as zip: for file in zip.namelist(): # Note: zip.extract cleans up any malicious file name # such as directory traversal attempts This is not the # case of zipfile.extractall zip.extract(file, path=os.path.join(target_directory, file)) # ❌ VULNERABLE ``` ### Root Cause The comment about `zip.extract()` fooled me at first :) then I noticed the `os.path.join()` call. The vulnerability stems from **incorrect usage of Python's `zipfile.ZipFile.extract()` API**: - The `path` parameter should be the **target directory**, not a full file path - `extract()` automatically appends the member name to the path - By passing `os.path.join(target_directory, file)`, GuardDog causes the filename to be appended **twice** - This breaks zipfile's built-in path traversal sanitization ### Attack Vector 1. Attacker creates malicious wheel with path traversal filenames 2. Uploads to PyPI or distributes directly 3. Package scan: `guarddog pypi scan malicious-pkg` 4. GuardDog downloads and extracts the package 5. Malicious files written to arbitrary locations 6. Code execution could be achieved ## Impact Impact depends on how GuardDog is running and under which environment. ### Critical Scenarios 1. **Immediate Code Execution** - Write to `~/.bashrc` → executes on next shell - Write to `~/.profile` → executes on login 2. **Persistent Backdoors** - Write to `~/.ssh/authorized_keys` → SSH access - Write to `/etc/cron.d/malicious` → scheduled execution (if root) - Write to systemd user services → persistent execution and more... ## Credits **Reported by:** Charbel (dwbruijn)
Affected packages (1)
- PyPI/guarddogfrom 0, < 2.7.1
CVSS scores
| Source | Version | Severity | Vector |
|---|---|---|---|
| osv | CVSS 4.0 | — | CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:P/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N |