{"answers":{"affected":"It affects 1 product.","exploited":"There is no known exploitation of CVE-2021-47646 in the wild and no public exploit code.","fix":"Apply the vendor's patch.","what":"CVE-2021-47646 is a high-severity use after free vulnerability in Linux kernel, published on 26 Feb 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-2021-47646 and fix it if it is affected.\n\nWhat it is: CVE-2021-47646 is a high-severity use after free vulnerability in Linux kernel, published on 26 Feb 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-2021-47646 in the wild and no public exploit code.\n\nAffected product: Linux kernel. 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-2021-47646/ (Markdown: https://insights.sbomify.com/CVE-2021-47646/index.md)","id":"CVE-2021-47646","markdown":"https://insights.sbomify.com/CVE-2021-47646/index.md","name":"CVE-2021-47646","record":{"aliases":["DEBIAN-CVE-2021-47646","GHSA-8qgg-vj9j-hh4r","UBUNTU-CVE-2021-47646"],"analysis":{"component_type":"kernel","fix_type":"patch","impacts":["denial_of_service"],"network_reachable":"adjacent_or_local","non_default_config":false,"product_category":"Linux kernel","requires_auth":"low_privilege","summary":"A use-after-free vulnerability in the Linux kernel BFQ I/O scheduler can cause a system crash, requiring a kernel patch to resolve.","user_interaction":"not_required","vuln_class":"use_after_free"},"analysis_generated_by":"qwen3.8-flash-next","assigner":"Linux","cpe":[{"product":"linux_kernel","vendor":"linux"}],"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":[{"id":"CWE-416","name":"Use After Free"}],"description":"In the Linux kernel, the following vulnerability has been resolved:\n\nRevert \"Revert \"block, bfq: honor already-setup queue merges\"\"\n\nA crash [1] happened to be triggered in conjunction with commit\n2d52c58b9c9b (\"block, bfq: honor already-setup queue merges\"). The\nlatter was then reverted by commit ebc69e897e17 (\"Revert \"block, bfq:\nhonor already-setup queue merges\"\"). Yet, the reverted commit was not\nthe one introducing the bug. In fact, it actually triggered a UAF\nintroduced by a different commit, and now fixed by commit d29bd41428cf\n(\"block, bfq: reset last_bfqq_created on group change\").\n\nSo, there is no point in keeping commit 2d52c58b9c9b (\"block, bfq:\nhonor already-setup queue merges\") out. This commit restores it.\n\n[1] https://bugzilla.kernel.org/show_bug.cgi?id=214503","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":"Revert \"Revert \"block, bfq: honor already-setup queue merges\"\"","id":"CVE-2021-47646","indexable":true,"kev":null,"kind":"cve","links":{"ecosystem":null,"product":"linux:linux_kernel","products":["linux:linux_kernel"],"type":"use_after_free","year":"2021"},"n_packages":0,"n_references":4,"next":{"headline":"clk: qcom: ipq8074: fix PCI-E clock oops","id":"CVE-2021-47647"},"packages":[],"prev":{"headline":"media: staging: media: zoran: calculate the right buffer number for zoran_reap_stat_com","id":"CVE-2021-47645"},"products":["Linux"],"published":"2025-02-26","related":[{"cvss_score":8.8,"headline":"Linux Kernel Out-of-Bounds Write","id":"CVE-2026-53266","kev_date_added":"2026-09-18","published":"2026-06-25"},{"cvss_score":8.8,"headline":"Linux Kernel Improper Input Validation","id":"CVE-2013-6282","kev_date_added":"2022-09-15","published":"2013-11-19"},{"cvss_score":8.4,"headline":"Linux Kernel Heap-Based Buffer Overflow","id":"CVE-2022-0185","kev_date_added":"2024-08-21","published":"2022-02-11"},{"cvss_score":8.4,"headline":"Linux Kernel Privilege Escalation","id":"CVE-2013-2094","kev_date_added":"2022-09-15","published":"2013-05-14"},{"cvss_score":7.8,"headline":"Linux Kernel Unspecified","id":"CVE-2026-53362","kev_date_added":"2026-08-27","published":"2026-07-04"},{"cvss_score":7.8,"headline":"Linux Kernel Missing Initialization of a Variable","id":"CVE-2026-46300","kev_date_added":"2026-10-28","published":"2026-05-23"},{"cvss_score":7.8,"headline":"Linux Kernel Race Condition","id":"CVE-2025-39964","kev_date_added":"2026-09-18","published":"2025-10-13"}],"sources":[{"class":"attribution","licence":"CVE Terms of Use (MITRE)","name":"CVE List","prefix":"CVE"},{"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":"none","technical_impact":"total"},"state":"PUBLISHED","updated":"2026-08-11","vendors":["Linux"]},"summary":"A use-after-free vulnerability in the Linux kernel BFQ I/O scheduler can cause a system crash, requiring a kernel patch to resolve.","url":"https://insights.sbomify.com/CVE-2021-47646/"}