CVE-2026-112935
filelock: SoftFileLock stale-lock break removes a live lock file on a reused inode number and admits two holders
Description
filelock is a platform-independent file lock for Python. From 3.22.0 until 4.2.1, SoftFileLock can break a stale marker after an attacker frees its own marker following the stale read, an honest contender creates a live successor on the reused inode, and the successor's modification time is not newer than the saved observation, causing the live marker to be removed and two holders to be admitted. This issue is fixed in version 4.2.1.
INFO
Published Date :
Oct. 20, 2026, 3:17 p.m.
Last Modified :
Oct. 21, 2026, 9:12 p.m.
Remotely Exploit :
No
Source :
[email protected]
CVSS Scores
| Score | Version | Severity | Vector | Exploitability Score | Impact Score | Source |
|---|---|---|---|---|---|---|
| CVSS 3.1 | MEDIUM | MITRE-CVE | ||||
| CVSS 3.1 | MEDIUM | [email protected] |
Solution
- Update filelock to version 4.2.1 or later.
References to Advisories, Solutions, and Tools
Here, you will find a curated list of external links that provide in-depth
information, practical solutions, and valuable tools related to
CVE-2026-112935.
| URL | Resource |
|---|---|
| https://github.com/tox-dev/filelock/commit/740ff666b62a88496c8d7394e4e6230605e4d62b | Patch |
| https://github.com/tox-dev/filelock/pull/843 | Patch |
| https://github.com/tox-dev/filelock/releases/tag/4.2.1 | Release Notes |
| https://github.com/tox-dev/filelock/security/advisories/GHSA-fq56-3cx3-fjxp | Exploit Mitigation Patch Vendor Advisory |
CWE - Common Weakness Enumeration
While CVE identifies
specific instances of vulnerabilities, CWE categorizes the common flaws or
weaknesses that can lead to vulnerabilities. CVE-2026-112935 is
associated with the following CWEs:
Common Attack Pattern Enumeration and Classification (CAPEC)
Common Attack Pattern Enumeration and Classification
(CAPEC)
stores attack patterns, which are descriptions of the common attributes and
approaches employed by adversaries to exploit the CVE-2026-112935
weaknesses.
We scan GitHub repositories to detect new proof-of-concept exploits. Following list is a collection of public exploits and proof-of-concepts, which have been published on GitHub (sorted by the most recently updated).
Results are limited to the first 15 repositories due to potential performance issues.
The following list is the news that have been mention
CVE-2026-112935 vulnerability anywhere in the article.
The following table lists the changes that have been made to the
CVE-2026-112935 vulnerability over time.
Vulnerability history details can be useful for understanding the evolution of a vulnerability, and for identifying the most recent changes that may impact the vulnerability's severity, exploitability, or other characteristics.
-
Initial Analysis by [email protected]
Oct. 21, 2026
Action Type Old Value New Value Added CPE Configuration OR *cpe:2.3:a:tox-dev:filelock:*:*:*:*:*:python:*:* versions from (including) 3.22.0 up to (excluding) 4.2.1 Added Reference Type GitHub, Inc.: https://github.com/tox-dev/filelock/commit/740ff666b62a88496c8d7394e4e6230605e4d62b Types: Patch Added Reference Type GitHub, Inc.: https://github.com/tox-dev/filelock/pull/843 Types: Patch Added Reference Type GitHub, Inc.: https://github.com/tox-dev/filelock/releases/tag/4.2.1 Types: Release Notes Added Reference Type GitHub, Inc.: https://github.com/tox-dev/filelock/security/advisories/GHSA-fq56-3cx3-fjxp Types: Exploit, Mitigation, Patch, Vendor Advisory -
New CVE Received by [email protected]
Oct. 20, 2026
Action Type Old Value New Value Added Description filelock is a platform-independent file lock for Python. From 3.22.0 until 4.2.1, SoftFileLock can break a stale marker after an attacker frees its own marker following the stale read, an honest contender creates a live successor on the reused inode, and the successor's modification time is not newer than the saved observation, causing the live marker to be removed and two holders to be admitted. This issue is fixed in version 4.2.1. Added CVSS V3.1 AV:L/AC:H/PR:L/UI:N/S:U/C:N/I:H/A:N Added CWE CWE-367 Added Affected New affected value received. <a href="https://github.com/CVEProject/cvelistV5/blob/main/cves/2026/112xxx/CVE-2026-112935.json">CVE-2026-112935</a> Added Reference https://github.com/tox-dev/filelock/commit/740ff666b62a88496c8d7394e4e6230605e4d62b Added Reference https://github.com/tox-dev/filelock/pull/843 Added Reference https://github.com/tox-dev/filelock/releases/tag/4.2.1 Added Reference https://github.com/tox-dev/filelock/security/advisories/GHSA-fq56-3cx3-fjxp