{"answers":{"affected":"It affects 1 product.","exploited":"There is no known exploitation of CVE-2021-47505 in the wild and no public exploit code.","fix":"Apply the vendor's patch.","what":"CVE-2021-47505 is a high-severity use after free vulnerability in Linux kernel, published on 24 May 2024. 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-2021-47505 and fix it if it is affected.\n\nWhat it is: CVE-2021-47505 is a high-severity use after free vulnerability in Linux kernel, published on 24 May 2024. 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-2021-47505 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-2021-47505/ (Markdown: https://insights.sbomify.com/CVE-2021-47505/index.md)","id":"CVE-2021-47505","markdown":"https://insights.sbomify.com/CVE-2021-47505/index.md","name":"CVE-2021-47505","record":{"aliases":["DEBIAN-CVE-2021-47505","UBUNTU-CVE-2021-47505"],"analysis":{"component_type":"kernel","fix_type":"patch","impacts":["code_execution","privilege_escalation"],"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's aio subsystem allows local attackers to potentially execute code or escalate privileges.","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\naio: fix use-after-free due to missing POLLFREE handling\n\nsignalfd_poll() and binder_poll() are special in that they use a\nwaitqueue whose lifetime is the current task, rather than the struct\nfile as is normally the case.  This is okay for blocking polls, since a\nblocking poll occurs within one task; however, non-blocking polls\nrequire another solution.  This solution is for the queue to be cleared\nbefore it is freed, by sending a POLLFREE notification to all waiters.\n\nUnfortunately, only eventpoll handles POLLFREE.  A second type of\nnon-blocking poll, aio poll, was added in kernel v4.18, and it doesn't\nhandle POLLFREE.  This allows a use-after-free to occur if a signalfd or\nbinder fd is polled with aio poll, and the waitqueue gets freed.\n\nFix this by making aio poll handle POLLFREE.\n\nA patch by Ramji Jiyani \u003cramjiyani@google.com\u003e\n(https://lore.kernel.org/r/20211027011834.2497484-1-ramjiyani@google.com)\ntried to do this by making aio_poll_wake() always complete the request\ninline if POLLFREE is seen.  However, that solution had two bugs.\nFirst, it introduced a deadlock, as it unconditionally locked the aio\ncontext while holding the waitqueue lock, which inverts the normal\nlocking order.  Second, it didn't consider that POLLFREE notifications\nare missed while the request has been temporarily de-queued.\n\nThe second problem was solved by my previous patch.  This patch then\nproperly fixes the use-after-free by handling POLLFREE in a\ndeadlock-free way.  It does this by taking advantage of the fact that\nfreeing of the waitqueue is RCU-delayed, similar to what eventpoll does.","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":"aio: fix use-after-free due to missing POLLFREE handling","id":"CVE-2021-47505","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":5,"next":{"headline":"nfsd: fix use-after-free due to delegation race","id":"CVE-2021-47506"},"packages":[],"prev":{"headline":"This CVE ID has been rejected or withdrawn by its CVE Numbering Authority.","id":"CVE-2021-47504"},"products":["Linux"],"published":"2024-05-24","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":"partial"},"state":"PUBLISHED","updated":"2026-08-05","vendors":["Linux"]},"summary":"A use-after-free vulnerability in the Linux kernel's aio subsystem allows local attackers to potentially execute code or escalate privileges.","url":"https://insights.sbomify.com/CVE-2021-47505/"}