{"answers":{"affected":"It affects 1 product.","exploited":"There is no known exploitation of CVE-2021-47391 in the wild and no public exploit code.","fix":"Apply the vendor's patch.","what":"CVE-2021-47391 is a high-severity use after free vulnerability in Linux kernel, published on 21 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-2021-47391 and fix it if it is affected.\n\nWhat it is: CVE-2021-47391 is a high-severity use after free vulnerability in Linux kernel, published on 21 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-2021-47391 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-2021-47391/ (Markdown: https://insights.sbomify.com/CVE-2021-47391/index.md)","id":"CVE-2021-47391","markdown":"https://insights.sbomify.com/CVE-2021-47391/index.md","name":"CVE-2021-47391","record":{"aliases":["DEBIAN-CVE-2021-47391","GHSA-xwrf-hhx9-vmhv","UBUNTU-CVE-2021-47391"],"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 race condition in the Linux kernel RDMA subsystem allows a use-after-free, potentially leading to code execution or privilege escalation.","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\nRDMA/cma: Ensure rdma_addr_cancel() happens before issuing more requests\n\nThe FSM can run in a circle allowing rdma_resolve_ip() to be called twice\non the same id_priv. While this cannot happen without going through the\nwork, it violates the invariant that the same address resolution\nbackground request cannot be active twice.\n\n       CPU 1                                  CPU 2\n\nrdma_resolve_addr():\n  RDMA_CM_IDLE -\u003e RDMA_CM_ADDR_QUERY\n  rdma_resolve_ip(addr_handler)  #1\n\n\t\t\t process_one_req(): for #1\n                          addr_handler():\n                            RDMA_CM_ADDR_QUERY -\u003e RDMA_CM_ADDR_BOUND\n                            mutex_unlock(\u0026id_priv-\u003ehandler_mutex);\n                            [.. handler still running ..]\n\nrdma_resolve_addr():\n  RDMA_CM_ADDR_BOUND -\u003e RDMA_CM_ADDR_QUERY\n  rdma_resolve_ip(addr_handler)\n    !! two requests are now on the req_list\n\nrdma_destroy_id():\n destroy_id_handler_unlock():\n  _destroy_id():\n   cma_cancel_operation():\n    rdma_addr_cancel()\n\n                          // process_one_req() self removes it\n\t\t          spin_lock_bh(\u0026lock);\n                           cancel_delayed_work(\u0026req-\u003ework);\n\t                   if (!list_empty(\u0026req-\u003elist)) == true\n\n      ! rdma_addr_cancel() returns after process_on_req #1 is done\n\n   kfree(id_priv)\n\n\t\t\t process_one_req(): for #2\n                          addr_handler():\n\t                    mutex_lock(\u0026id_priv-\u003ehandler_mutex);\n                            !! Use after free on id_priv\n\nrdma_addr_cancel() expects there to be one req on the list and only\ncancels the first one. The self-removal behavior of the work only happens\nafter the handler has returned. This yields a situations where the\nreq_list can have two reqs for the same \"handle\" but rdma_addr_cancel()\nonly cancels the first one.\n\nThe second req remains active beyond rdma_destroy_id() and will\nuse-after-free id_priv once it inevitably triggers.\n\nFix this by remembering if the id_priv has called rdma_resolve_ip() and\nalways cancel before calling it again. This ensures the req_list never\ngets more than one item in it and doesn't cost anything in the normal flow\nthat never uses this strange error path.","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":"RDMA/cma: Ensure rdma_addr_cancel() happens before issuing more requests","id":"CVE-2021-47391","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":3,"next":{"headline":"RDMA/cma: Fix listener leak in rdma_cma_listen_on_all() failure","id":"CVE-2021-47392"},"packages":[],"prev":{"headline":"KVM: x86: Fix stack-out-of-bounds memory access from ioapic_write_indirect()","id":"CVE-2021-47390"},"products":["Linux"],"published":"2024-05-21","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 race condition in the Linux kernel RDMA subsystem allows a use-after-free, potentially leading to code execution or privilege escalation.","url":"https://insights.sbomify.com/CVE-2021-47391/"}