low2.5
CVE-2026-112912
filelock: Symlink swap during SoftFileLock's writability check leaks whether a path exists and is writable by the lock taker
Impact
filelock is a platform-independent file lock for Python. From 3.32.6 until 4.2.1, SoftFileLock can follow a swapped symbolic link during the conditional os.access writability check for a node without its owner-write bit, allowing another local user on a platform and directory configuration that follows the link to infer whether a chosen path exists and is writable from the observable acquisition result. This issue is fixed in version 4.2.1.
Affected packages
| Ecosystem | Package | Affected | Fixed in |
|---|---|---|---|
| pip | filelock | >= 3.32.6, <= 4.2.0 | 4.2.1 |
Affected products
| Vendor | Product | Affected versions |
|---|---|---|
| Tox-Dev | Filelock | from 3.32.6 before 4.2.1 |
Weakness classification
References
- NVD record
- CVE.org record
- GitHub advisory
- https://github.com/advisories/GHSA-9j6q-wvj5-jgjg
- https://github.com/tox-dev/filelock/security/advisories/GHSA-9j6q-wvj5-jgjg
- https://nvd.nist.gov/vuln/detail/CVE-2026-112912
- https://github.com/tox-dev/filelock/pull/835
- https://github.com/tox-dev/filelock/commit/e1e825b1992f69fb6b346dc395d5ae4893536c0a
- https://github.com/tox-dev/filelock/releases/tag/4.2.1