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Fencer Vulns
medium 6.3

CVE-2026-112911 json

filelock: StrictSoftFileLock and SoftReadWriteLock adopt a protocol directory another user created first, losing mutual exclusion

published 2026-10-20 19 d ago modified 2026-10-28 11 d ago also GHSA-9c4x-gm8v-wgc4 , EUVD-2026-105018

cvss
6.3
version 3.1, CNA
cisa kev
Not listed
not in CISA's catalog
epss
0.1%
EPSS 0.1% chance of exploitation in 30 days, percentile 3%
public exploits
0
none known

Summary

filelock is a platform-independent file lock for Python. From 3.30.0 until 4.2.1, StrictSoftFileLock versions from 3.30.0 and SoftReadWriteLock versions from 4.0.0 can adopt a protocol directory created first by another local user in a shared parent directory, allowing that user to alter protocol state and admit concurrent holders. This issue is fixed in version 4.2.1.

Patch / fix

  • pypi filelock 4.2.1
  • tox-dev filelock 4.2.1

Vendor advisories

What the vendors themselves say about their products: affected, fixed or not affected, and what to do.

red hat product security vex CVE-2026-112911 updated cvss 6.3

filelock: filelock: Lock bypass via pre-created shared protocol directory

  • Red Hat Ansible Automation Orchestrator 2026 ansible-automation-platform/automation-orchestrator-backend-rhel9
    affected: no fix available “Fix deferred”
  • Red Hat Exploit Intelligence exploit-intelligence/vulnerability-analysis-rhel9
    affected: no fix planned “Out of support scope”
  • Red Hat Lightspeed Core lightspeed-core/rag-tool-cpu-rhel9, lightspeed-core/lightspeed-stack-rhel9, lightspeed-core/rag-tool-cuda-12.9-rhel9 Red Hat Lightspeed Services for Advanced Cluster Management lightspeed-services-acm/ocp-rules-rhel9 Red Hat OpenShift Lightspeed openshift-lightspeed/lightspeed-ocp-rag-rhel9, openshift-lightspeed/lightspeed-service-api-rhel9, openshift-lightspeed-tech-preview/lightspeed-rag-tool-rhel9 Red Hat Pen Drive Powered by Red Hat Lightspeed pen-drive/pen-drive-scanner-rhel9 Red Hat AI Inference Server rhaii/vllm-cpu-rhel9, rhaii/vllm-tpu-rhel9, rhaii/vllm-cuda-rhel9, rhaii/vllm-rocm-rhel9, rhaiis/vllm-cpu-rhel9, rhaiis/vllm-tpu-rhel9, +9 more
    affected: no fix available “Fix deferred”
  • Red Hat Ansible Automation Platform 2 python-filelock 3.8.0-1.el9ap, python3x-filelock 3.8.0-1.el8ap, python3.11-filelock 3.13.1-1.el9ap, python3.12-filelock 3.13.1-2.el9ap, automation-controller 4.5.37-1.el8ap, ansible-automation-platform-26/hub-rhel9, +18 more Red Hat Ansible Automation Platform Ansible Core 2 ansible-automation-platform/ee-minimal-rhel8, ansible-automation-platform/ee-minimal-rhel9, ansible-automation-platform-tech-preview/ee-minimal-rhel8, ansible-automation-platform-tech-preview/ee-minimal-rhel9
    affected: no fix available, no fix planned “Out of support scope”
  • Red Hat Enterprise Linux AI (RHEL AI) 3 rhelai3/bootc-cuda-rhel9, rhelai3/bootc-rocm-rhel9, rhelai3/bootc-gaudi-rhel9, rhelai3/bootc-aws-cuda-rhel9, rhelai3/bootc-gcp-cuda-rhel9, rhelai3/disk-image-cuda-rhel9, +2 more Red Hat Lightspeed Services for OCP lightspeed-services-ocp/ocp-rules-rhel9 Red Hat OpenShift AI (RHOAI) rhai/guidellm-rhel9, rhoai/odh-automl-rhel9, rhoai/odh-mlflow-rhel9, rhoai/odh-autorag-rhel9, rhoai/odh-ogx-core-rhel9, rhoai/odh-caikit-nlp-rhel9, +49 more Red Hat OpenShift Container Platform 4 python-filelock 3.8.0-1.el9ap Red Hat OpenShift Dev Spaces devspaces/udi-rhel9 Red Hat Satellite 6 satellite/iop-puptoo-rhel9, satellite/iop-yuptoo-rhel9, satellite/iop-advisor-engine-rhel9, satellite/iop-host-inventory-rhel9, satellite/iop-advisor-backend-rhel9, satellite/iop-insights-engine-rhel9
    affected: no fix available “Fix deferred”

Red Hat CSAF VEX © Red Hat, Inc., from https://security.access.redhat.com/data/csaf/v2/vex/; changed: reduced to product statuses and remediations. CC BY 4.0 · csaf

CISA SSVC

Exploitation
Proof of concept is public
Automatable
no
Technical impact
partial
Assessed
11 d ago

Exploit prediction

0.15% chance of exploitation in the next 30 days, higher than 3% of all scored CVEs (FIRST EPSS, 2026-11-08).

Exploits and checks

  • github.com https://github.com/tox-dev/filelock/security/advisories/GHSA-9c4x-gm8v-wgc4 referenced PoC, tagged "exploit" by a source, unverified

CVSS scores

assigned by version score vector
CNA 3.1 6.3 CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:N/I:H/A:H
GitHub 3.1 6.3 CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:N/I:H/A:H

Affected packages

ecosystem package affected fixed in
pypi filelock
>=3.30.0, <4.2.1
4.2.1

Affected products

  • tox-dev filelock

Classification

Weakness

References

Sources

Fencer Vulns keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.