{"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-2026-112909 exists.","fix":"Upgrade filelock to 4.2.1 or later.","what":"CVE-2026-112909 is a medium-severity vulnerability in tox-dev filelock, published on 20 Oct 2026."},"fix_prompt":"Check this codebase for CVE-2026-112909 and fix it if it is affected.\n\nWhat it is: CVE-2026-112909 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-2026-112909 exists.\n\nAffected packages and fixed versions:\n- filelock (PyPI): affected all versions; fixed in 4.2.1\n- filelock (PyPI): affected all versions; 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-2026-112909/ (Markdown: https://insights.sbomify.com/CVE-2026-112909/index.md)","id":"CVE-2026-112909","markdown":"https://insights.sbomify.com/CVE-2026-112909/index.md","name":"CVE-2026-112909","record":{"aliases":["AZL-110067","CLEANSTART-2026-ZN36596","DEBIAN-CVE-2026-112909","GHSA-69hj-f68j-2879","MINI-5vrg-6385-j6xg","MINI-vmj9-r77g-8m2h","UBUNTU-CVE-2026-112909"],"analysis":null,"analysis_generated_by":null,"assigner":"GitHub_M","cpe":[{"product":"filelock","vendor":"tox-dev"}],"cvss":{"score":6.1,"severity":"medium","source":"cna","vector":"CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:L/I:H/A:N","version":"3.1"},"cwes":[{"id":"CWE-706","name":"Use of Incorrectly-Resolved Name or Reference"}],"description":"filelock is a platform-independent file lock for Python. Prior to 4.2.1, UnixFileLock can truncate a regular file renamed onto the lock path when another local user has actual rename permission, or hard-linked there under a permissive hard-link policy; when an explicit mode is requested, affected versions from 3.10.2 can also change that file's mode. 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: UnixFileLock truncates and chmods any regular file another user renames or hard-links onto the lock path","id":"CVE-2026-112909","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: StrictSoftFileLock and SoftReadWriteLock adopt a protocol directory another user created first, losing mutual exclusion","id":"CVE-2026-112911"},"packages":[{"ecosystem":"PyPI","fixed":["4.2.1"],"introduced":["0"],"last_affected":[],"package":"filelock","purl":null,"source":"GHSA-69hj-f68j-2879"},{"ecosystem":"PyPI","fixed":["4.2.1"],"introduced":["0"],"last_affected":[],"package":"filelock","purl":"pkg:pypi/filelock","source":"GHSA-69hj-f68j-2879"}],"prev":{"headline":"filelock: SoftFileLock evicts a fresh lock file whose watched age another local user's pre-dated file passed on through inode reuse","id":"CVE-2026-112906"},"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: 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":"2026-10-22","vendors":["tox-dev"]},"summary":null,"url":"https://insights.sbomify.com/CVE-2026-112909/"}