CVE-2026-112912: filelock — Exploit & Fix

Description

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.

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CVSS v3.1 Score

2.5

LOW

CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:L/I:N/A:N

EPSS — Exploit Prediction

0.0021

Probability of exploitation

0.11%

Percentile rank

EPSS estimates the probability that this vulnerability will be exploited in the wild within the next 30 days. A higher score means more likely to be exploited.

Weakness Type (CWE)

CWE-59 CWE-59

Affected Products

Vendor	Product	Versions
tox-dev	filelock	3.32.6 — 4.2.1

References

Advisories & Patches

https://github.com/tox-dev/filelock/commit/e1e825b1992f69fb6b346dc395d5ae4893536c0a https://github.com/tox-dev/filelock/pull/835 https://github.com/tox-dev/filelock/security/advisories/GHSA-9j6q-wvj5-jgjg https://github.com/tox-dev/filelock/security/advisories/GHSA-9j6q-wvj5-jgjg

Exploits

https://github.com/tox-dev/filelock/security/advisories/GHSA-9j6q-wvj5-jgjg https://github.com/tox-dev/filelock/security/advisories/GHSA-9j6q-wvj5-jgjg

Other References

https://github.com/tox-dev/filelock/releases/tag/4.2.1

Frequently Asked Questions

What is CVE-2026-112912? +

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. It has a CVSS v3.1 base score of 2.5 (LOW).

How severe is CVE-2026-112912? +

CVE-2026-112912 has a CVSS v3.1 score of 2.5 out of 10, rated LOW. This is a low-severity vulnerability with limited impact. The EPSS score is 0.0021, placing it in the 0th percentile for exploitation probability.

What products are affected by CVE-2026-112912? +

CVE-2026-112912 affects products from tox-dev, specifically: filelock. Check the affected products table above for specific version ranges.

How do I check if I'm vulnerable to CVE-2026-112912? +

You can use Secably's free Website Scanner to check your website for known vulnerabilities. For infrastructure scanning, use the Port Scanner to identify exposed services that may be affected. Check the vendor advisories linked above for specific patch and version information.

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