{"answers":{"affected":"2 open source packages ship an affected version, including filelock. It affects 1 product.","exploited":"It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-112939 exists.","fix":"Upgrade filelock to 4.2.1 or later.","what":"CVE-2026-112939 is a medium-severity vulnerability in tox-dev filelock, published on 20 Oct 2026."},"fix_prompt":"Check this codebase for CVE-2026-112939 and fix it if it is affected.\n\nWhat it is: CVE-2026-112939 is a medium-severity vulnerability in tox-dev filelock, published on 20 Oct 2026. \nExploitation: It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-112939 exists.\n\nAffected packages and fixed versions:\n- filelock (PyPI): affected from 3.22.0; fixed in 4.2.1\n- filelock (PyPI): affected from 3.22.0; fixed in 4.2.1\n\nTask:\n1. Search the dependency manifests and lockfiles (for example package.json, package-lock.json, requirements.txt, poetry.lock, uv.lock, pom.xml, build.gradle, go.mod, Cargo.lock, Gemfile.lock) and any Dockerfiles for the affected packages, including transitive dependencies.\n2. If an affected version is in use, upgrade it to the fixed version for its release line with the project's package manager, so the lockfile is regenerated. Prefer the smallest upgrade that fixes it.\n3. If there is no fix, or the upgrade would break the build, do not guess: explain the risk and the safest workaround instead.\n4. Run the tests and summarise what changed and why.\n5. If nothing in the project is affected, say so and change nothing.\n\nReference: https://insights.sbomify.com/CVE-2026-112939/ (Markdown: https://insights.sbomify.com/CVE-2026-112939/index.md)","id":"CVE-2026-112939","markdown":"https://insights.sbomify.com/CVE-2026-112939/index.md","name":"CVE-2026-112939","record":{"aliases":["CLEANSTART-2026-AU42206","DEBIAN-CVE-2026-112939","GHSA-rfpc-qcw5-3pc4","MINI-grpq-3wj4-6jwp","UBUNTU-CVE-2026-112939"],"analysis":null,"analysis_generated_by":null,"assigner":"GitHub_M","cpe":[{"product":"filelock","vendor":"tox-dev"}],"cvss":{"score":4.7,"severity":"medium","source":"cna","vector":"CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:N/I:H/A:N","version":"3.1"},"cwes":[{"id":"CWE-345","name":"Insufficient Verification of Data Authenticity"}],"description":"filelock is a platform-independent file lock for Python. From 3.22.0 until 4.2.1, SoftFileLock can trust a forged process identifier in a marker that an attacker can modify but cannot remove, allowing an authorized contender such as another process of the holder's account or root to act as a confused deputy, remove the live marker, and admit another holder. This issue is fixed in version 4.2.1.","ecosystems":["PyPI"],"exploits":{"exploitdb":0,"first_seen":null,"github_poc":0,"max_poc_stars":null,"metasploit":0,"nuclei":0,"refs":[],"tier":"weaponised"},"has_fix":true,"headline":"filelock: SoftFileLock removes a live holder's marker when another user forges the PID in a writable marker","id":"CVE-2026-112939","indexable":true,"kev":null,"kind":"cve","links":{"ecosystem":"PyPI","product":null,"products":[],"type":null,"year":"2026"},"n_packages":2,"n_references":4,"next":{"headline":"filelock ReadWriteLock: SQLite reopens the lock database by name, so a planted symlink or journal file makes the lock user's process overwrite or unlink its own files","id":"CVE-2026-112940"},"packages":[{"ecosystem":"PyPI","fixed":["4.2.1"],"introduced":["3.22.0"],"last_affected":[],"package":"filelock","purl":null,"source":"GHSA-rfpc-qcw5-3pc4"},{"ecosystem":"PyPI","fixed":["4.2.1"],"introduced":["3.22.0"],"last_affected":[],"package":"filelock","purl":"pkg:pypi/filelock","source":"GHSA-rfpc-qcw5-3pc4"}],"prev":{"headline":"filelock: ReadWriteLock on the hard-link route deletes any directory another user renames onto its .filelock-* link directory name","id":"CVE-2026-112937"},"products":["filelock"],"published":"2026-10-20","related":[{"cvss_score":7.1,"headline":"filelock ReadWriteLock: SQLite reopens the lock database by name, so a planted symlink or journal file makes the lock user's process overwrite or unlink its own files","id":"CVE-2026-112940","kev_date_added":null,"published":"2026-10-20"},{"cvss_score":6.3,"headline":"filelock: StrictSoftFileLock and SoftReadWriteLock adopt a protocol directory another user created first, losing mutual exclusion","id":"CVE-2026-112911","kev_date_added":null,"published":"2026-10-20"},{"cvss_score":6.3,"headline":"filelock has TOCTOU race condition that allows symlink attacks during lock file creation","id":"CVE-2025-68146","kev_date_added":null,"published":"2025-12-16"},{"cvss_score":6.1,"headline":"filelock: UnixFileLock truncates and chmods any regular file another user renames or hard-links onto the lock path","id":"CVE-2026-112909","kev_date_added":null,"published":"2026-10-20"},{"cvss_score":6.1,"headline":"filelock: SoftReadWriteLock holder refresh writes through a hard link and hangs on a named pipe that another local user renames over its record","id":"CVE-2026-112934","kev_date_added":null,"published":"2026-10-20"},{"cvss_score":6.1,"headline":"filelock: ReadWriteLock follows a symlink at the lock path into SQLite","id":"CVE-2026-112936","kev_date_added":null,"published":"2026-10-20"},{"cvss_score":6.1,"headline":"filelock: ReadWriteLock on the hard-link route deletes any directory another user renames onto its .filelock-* link directory name","id":"CVE-2026-112937","kev_date_added":null,"published":"2026-10-20"}],"sources":[{"class":"attribution","licence":"CVE Terms of Use (MITRE)","name":"CVE List","prefix":"CVE"},{"class":"attribution","licence":"CC BY 4.0","name":"GitHub Advisory Database","prefix":"GHSA"},{"class":"attribution","licence":"US public information, NVD API terms","name":"NVD"},{"class":"attribution","licence":"CWE Terms of Use","name":"CWE (MITRE)"},{"class":"attribution","licence":"FIRST CVSS licence","name":"CVSS (FIRST)"}],"ssvc":{"automatable":"no","exploitation":"poc","technical_impact":"partial"},"state":"PUBLISHED","updated":"2026-10-20","vendors":["tox-dev"]},"summary":null,"url":"https://insights.sbomify.com/CVE-2026-112939/"}