CVE-2026-112912filelock: Symlink swap during SoftFileLock's writability check leaks whether a path exists and is writable by the lock taker
Updated under an hour ago ()
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It affects tox-dev filelock. Add what you run to find out whether that includes you.
No exploitation reported and no EPSS estimate yet.
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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.
- CVSS
- 2.5 LOW (v3.1, CNA)CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:L/I:N/A:N
- Weakness (CWE)
- CWE-59
- Known exploited
- Not in CISA's KEV catalog
- EPSS (exploitation in the next 30 days)
- Not loaded for this CVE
- Assigned by
- GitHub_M
- NVD analysis
- Undergoing Analysis
- Record last updated
- Oct 20, 2026
- First seen by InfoSec Signals
- Oct 20, 2026
Affected products
tox-dev filelock tox_dev:filelock (from the name) | from 3.32.6, < 4.2.1 | CNA record |
References
- https://github.com/tox-dev/filelock/security/advisories/GHSA-9j6q-wvj5-jgjgx-refsource-confirm
- https://github.com/tox-dev/filelock/pull/835x-refsource-misc
- https://github.com/tox-dev/filelock/commit/e1e825b1992f69fb6b346dc395d5ae4893536c0ax-refsource-misc
- https://github.com/tox-dev/filelock/releases/tag/4.2.1x-refsource-misc
The CVE record on cve.org NVD's entry
The CVE record is authoritative. Products marked “from the name” were identified from the CNA's free-text names, not a CPE, and are matched less certainly. This product uses the NVD API but is not endorsed or certified by the NVD.