{"answers":{"affected":"","exploited":"There is no known exploitation of CVE-2025-40303 in the wild and no public exploit code.","fix":"Apply the vendor's patch.","what":"CVE-2025-40303 is a high-severity use after free vulnerability in Linux, published on 8 Dec 2025. It can only be exploited from the same machine or local network, with no action from the victim."},"fix_prompt":"Check this codebase for CVE-2025-40303 and fix it if it is affected.\n\nWhat it is: CVE-2025-40303 is a high-severity use after free vulnerability in Linux, published on 8 Dec 2025. It can only be exploited from the same machine or local network, with no action from the victim.\nExploitation: There is no known exploitation of CVE-2025-40303 in the wild and no public exploit code.\n\nAffected product: Linux. No package-level version data is available, so check the vendor advisory linked from the reference page.\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-2025-40303/ (Markdown: https://insights.sbomify.com/CVE-2025-40303/index.md)","id":"CVE-2025-40303","markdown":"https://insights.sbomify.com/CVE-2025-40303/index.md","name":"CVE-2025-40303","record":{"aliases":["BELL-CVE-2025-40303","DEBIAN-CVE-2025-40303","GHSA-5q2h-f93q-8fv2","ROOT-OS-DEBIAN-11-CVE-2025-40303","ROOT-OS-DEBIAN-12-CVE-2025-40303","ROOT-OS-DEBIAN-13-CVE-2025-40303","ROOT-OS-UBUNTU-2204-CVE-2025-40303","ROOT-OS-UBUNTU-2404-CVE-2025-40303","UBUNTU-CVE-2025-40303"],"analysis":{"component_type":"kernel","fix_type":"patch","impacts":["denial_of_service","code_execution"],"network_reachable":"adjacent_or_local","non_default_config":true,"product_category":"Linux kernel btrfs","requires_auth":"low_privilege","summary":"A use-after-free in the Linux kernel btrfs filesystem can cause crashes or potential code execution when dirty metadata is written back after worker threads are stopped.","user_interaction":"not_required","vuln_class":"use_after_free"},"analysis_generated_by":"qwen3.8-flash-next","assigner":"Linux","cpe":[],"cvss":{"score":7.8,"severity":"high","source":"cna","vector":"CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H","version":"3.1"},"cwes":[],"description":"In the Linux kernel, the following vulnerability has been resolved:\n\nbtrfs: ensure no dirty metadata is written back for an fs with errors\n\n[BUG]\nDuring development of a minor feature (make sure all btrfs_bio::end_io()\nis called in task context), I noticed a crash in generic/388, where\nmetadata writes triggered new works after btrfs_stop_all_workers().\n\nIt turns out that it can even happen without any code modification, just\nusing RAID5 for metadata and the same workload from generic/388 is going\nto trigger the use-after-free.\n\n[CAUSE]\nIf btrfs hits an error, the fs is marked as error, no new\ntransaction is allowed thus metadata is in a frozen state.\n\nBut there are some metadata modifications before that error, and they are\nstill in the btree inode page cache.\n\nSince there will be no real transaction commit, all those dirty folios\nare just kept as is in the page cache, and they can not be invalidated\nby invalidate_inode_pages2() call inside close_ctree(), because they are\ndirty.\n\nAnd finally after btrfs_stop_all_workers(), we call iput() on btree\ninode, which triggers writeback of those dirty metadata.\n\nAnd if the fs is using RAID56 metadata, this will trigger RMW and queue\nnew works into rmw_workers, which is already stopped, causing warning\nfrom queue_work() and use-after-free.\n\n[FIX]\nAdd a special handling for write_one_eb(), that if the fs is already in\nan error state, immediately mark the bbio as failure, instead of really\nsubmitting them.\n\nThen during close_ctree(), iput() will just discard all those dirty\ntree blocks without really writing them back, thus no more new jobs for\nalready stopped-and-freed workqueues.\n\nThe extra discard in write_one_eb() also acts as an extra safenet.\nE.g. the transaction abort is triggered by some extent/free space\ntree corruptions, and since extent/free space tree is already corrupted\nsome tree blocks may be allocated where they shouldn't be (overwriting\nexisting tree blocks). In that case writing them back will further\ncorrupting the fs.","ecosystems":[],"exploits":{"exploitdb":0,"first_seen":null,"github_poc":0,"max_poc_stars":null,"metasploit":0,"nuclei":0,"refs":[],"tier":"none_known"},"has_fix":true,"headline":"btrfs: ensure no dirty metadata is written back for an fs with errors","id":"CVE-2025-40303","indexable":true,"kev":null,"kind":"cve","links":{"ecosystem":null,"product":null,"products":[],"type":"use_after_free","year":"2025"},"n_packages":0,"n_references":4,"next":{"headline":"fbdev: Add bounds checking in bit_putcs to fix vmalloc-out-of-bounds","id":"CVE-2025-40304"},"packages":[],"prev":{"headline":"media: videobuf2: forbid remove_bufs when legacy fileio is active","id":"CVE-2025-40302"},"products":["Linux"],"published":"2025-12-08","related":[],"sources":[{"class":"attribution","licence":"CVE Terms of Use (MITRE)","name":"CVE List","prefix":"CVE"},{"class":"attribution","licence":"FIRST CVSS licence","name":"CVSS (FIRST)"}],"ssvc":{"automatable":null,"exploitation":null,"technical_impact":null},"state":"PUBLISHED","updated":"2026-08-05","vendors":["Linux"]},"summary":"A use-after-free in the Linux kernel btrfs filesystem can cause crashes or potential code execution when dirty metadata is written back after worker threads are stopped.","url":"https://insights.sbomify.com/CVE-2025-40303/"}