CVE-2026-40258 is a critical-severity (CVSS 9.1) Path Traversal vulnerability in gramps-webapi. A fix is available for gramps-webapi — see the affected versions and patch details below.
Gramps Web API has Zip Slip Path Traversal in Media Archive Import
EPSS Exploitation Probability
Probability of exploitation in the next 30 days, from FIRST.org EPSS.
How urgent is this, really
Where this sits among everything scored
Real-World Exposure
gramps-webapiReal-time download stats are indexed for npm and PyPI packages. This vulnerability affects PyPI packages — download data is not available via public APIs for these ecosystems.
Description
Summary
A path traversal vulnerability (Zip Slip) exists in the media archive import feature. An authenticated user with owner-level privileges can craft a malicious ZIP file with directory-traversal filenames to write arbitrary files outside the intended temporary extraction directory on the server's local filesystem.
Details
When importing media archives as ZIP file, MediaImporter._check_disk_space_and_extract() in gramps_webapi/api/media_importer.py called zipfile.extractall() without validating ZIP entry names. Python's zipfile module does not sanitize entry names containing ../ sequences, allowing extraction to paths outside the target directory.
Only users with owner permission can upload media ZIP archives, so the biggest risk is for multi-tree deployments, where tree owners are distinct from server administrators.
For multi-tree deployments, the impact depends on deployment configuration. Assuming the standard docker-based deployment is used:
- SQLite family tree + local media: An attacker can overwrite another tree's database file or media files, leading to cross-tree data corruption or replacement.
- Postgres family tree + S3 media: No persistent tree data is stored on the local filesystem, so cross-tree impact is eliminated. The remaining risk is overwriting volume-mounted files such as the application config file.
- Postgres family tree + S3 media + environment-variable-only config: No persistent files of value are present on the local filesystem. Impact is limited to writes to ephemeral container storage, which are lost on woker restart.
Fix
ZIP entry names are now validated against the resolved real path of the temporary directory before extraction. Any entry whose resolved path falls outside the temporary directory raises an error and aborts the import.
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| 🐍PyPI | gramps-webapi | ≥ 1.6.0&&< 3.11.1 | 3.11.1pip install --upgrade 'gramps-webapi==3.11.1' |
Detection & mitigation playbook
Open-source dependencyDetect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for gramps-webapi, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.
Fix
Update gramps-webapi to 3.11.1 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2026-40258 is resolved across your whole dependency graph.
Workarounds
Resolve every user-supplied path to its canonical form and reject anything that escapes the intended directory, and run the component under an account that has no read or write access outside the directory it legitimately serves.
Frequently Asked Questions
Is CVE-2026-40258 in your dependencies?
Find it across PyPI, including transitive dependencies.