{"answers":{"affected":"It affects 1 product.","exploited":"There is no known exploitation of CVE-2024-40899 in the wild and no public exploit code.","fix":"Apply the vendor's patch.","what":"CVE-2024-40899 is a high-severity use after free vulnerability in Linux kernel, published on 12 Jul 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-2024-40899 and fix it if it is affected.\n\nWhat it is: CVE-2024-40899 is a high-severity use after free vulnerability in Linux kernel, published on 12 Jul 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-2024-40899 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-2024-40899/ (Markdown: https://insights.sbomify.com/CVE-2024-40899/index.md)","id":"CVE-2024-40899","markdown":"https://insights.sbomify.com/CVE-2024-40899/index.md","name":"CVE-2024-40899","record":{"aliases":["BELL-CVE-2024-40899","DEBIAN-CVE-2024-40899","GHSA-8jvx-wqf8-m6ph","UBUNTU-CVE-2024-40899"],"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 cachefiles subsystem allows local attackers to execute arbitrary 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":"nvd","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\ncachefiles: fix slab-use-after-free in cachefiles_ondemand_get_fd()\n\nWe got the following issue in a fuzz test of randomly issuing the restore\ncommand:\n\n==================================================================\nBUG: KASAN: slab-use-after-free in cachefiles_ondemand_daemon_read+0x609/0xab0\nWrite of size 4 at addr ffff888109164a80 by task ondemand-04-dae/4962\n\nCPU: 11 PID: 4962 Comm: ondemand-04-dae Not tainted 6.8.0-rc7-dirty #542\nCall Trace:\n kasan_report+0x94/0xc0\n cachefiles_ondemand_daemon_read+0x609/0xab0\n vfs_read+0x169/0xb50\n ksys_read+0xf5/0x1e0\n\nAllocated by task 626:\n __kmalloc+0x1df/0x4b0\n cachefiles_ondemand_send_req+0x24d/0x690\n cachefiles_create_tmpfile+0x249/0xb30\n cachefiles_create_file+0x6f/0x140\n cachefiles_look_up_object+0x29c/0xa60\n cachefiles_lookup_cookie+0x37d/0xca0\n fscache_cookie_state_machine+0x43c/0x1230\n [...]\n\nFreed by task 626:\n kfree+0xf1/0x2c0\n cachefiles_ondemand_send_req+0x568/0x690\n cachefiles_create_tmpfile+0x249/0xb30\n cachefiles_create_file+0x6f/0x140\n cachefiles_look_up_object+0x29c/0xa60\n cachefiles_lookup_cookie+0x37d/0xca0\n fscache_cookie_state_machine+0x43c/0x1230\n [...]\n==================================================================\n\nFollowing is the process that triggers the issue:\n\n     mount  |   daemon_thread1    |    daemon_thread2\n------------------------------------------------------------\n cachefiles_ondemand_init_object\n  cachefiles_ondemand_send_req\n   REQ_A = kzalloc(sizeof(*req) + data_len)\n   wait_for_completion(\u0026REQ_A-\u003edone)\n\n            cachefiles_daemon_read\n             cachefiles_ondemand_daemon_read\n              REQ_A = cachefiles_ondemand_select_req\n              cachefiles_ondemand_get_fd\n              copy_to_user(_buffer, msg, n)\n            process_open_req(REQ_A)\n                                  ------ restore ------\n                                  cachefiles_ondemand_restore\n                                  xas_for_each(\u0026xas, req, ULONG_MAX)\n                                   xas_set_mark(\u0026xas, CACHEFILES_REQ_NEW);\n\n                                  cachefiles_daemon_read\n                                   cachefiles_ondemand_daemon_read\n                                    REQ_A = cachefiles_ondemand_select_req\n\n             write(devfd, (\"copen %u,%llu\", msg-\u003emsg_id, size));\n             cachefiles_ondemand_copen\n              xa_erase(\u0026cache-\u003ereqs, id)\n              complete(\u0026REQ_A-\u003edone)\n   kfree(REQ_A)\n                                    cachefiles_ondemand_get_fd(REQ_A)\n                                     fd = get_unused_fd_flags\n                                     file = anon_inode_getfile\n                                     fd_install(fd, file)\n                                     load = (void *)REQ_A-\u003emsg.data;\n                                     load-\u003efd = fd;\n                                     // load UAF !!!\n\nThis issue is caused by issuing a restore command when the daemon is still\nalive, which results in a request being processed multiple times thus\ntriggering a UAF. So to avoid this problem, add an additional reference\ncount to cachefiles_req, which is held while waiting and reading, and then\nreleased when the waiting and reading is over.\n\nNote that since there is only one reference count for waiting, we need to\navoid the same request being completed multiple times, so we can only\ncomplete the request if it is successfully removed from the xarray.","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":"cachefiles: fix slab-use-after-free in cachefiles_ondemand_get_fd()","id":"CVE-2024-40899","indexable":true,"kev":null,"kind":"cve","links":{"ecosystem":null,"product":"linux:linux_kernel","products":["linux:linux_kernel"],"type":"use_after_free","year":"2024"},"n_packages":0,"n_references":4,"next":{"headline":"cachefiles: remove requests from xarray during flushing requests","id":"CVE-2024-40900"},"packages":[],"prev":{"headline":"Apache HTTP Server: SSRF with mod_rewrite in server/vhost context on Windows","id":"CVE-2024-40898"},"products":["Linux"],"published":"2024-07-12","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":"2026-05-11","vendors":["Linux"]},"summary":"A use-after-free vulnerability in the Linux kernel's cachefiles subsystem allows local attackers to execute arbitrary code or escalate privileges.","url":"https://insights.sbomify.com/CVE-2024-40899/"}