{"dataType":"CVE_RECORD","dataVersion":"5.2","cveMetadata":{"cveId":"CVE-2021-47089","assignerOrgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","state":"PUBLISHED","assignerShortName":"Linux","dateReserved":"2024-02-29T22:33:44.300Z","datePublished":"2024-03-04T18:10:27.495Z","dateUpdated":"2026-05-11T13:47:49.944Z"},"containers":{"cna":{"providerMetadata":{"orgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","shortName":"Linux","dateUpdated":"2026-05-11T13:47:49.944Z"},"descriptions":[{"lang":"en","value":"In the Linux kernel, the following vulnerability has been resolved:\n\nkfence: fix memory leak when cat kfence objects\n\nHulk robot reported a kmemleak problem:\n\n    unreferenced object 0xffff93d1d8cc02e8 (size 248):\n      comm \"cat\", pid 23327, jiffies 4624670141 (age 495992.217s)\n      hex dump (first 32 bytes):\n        00 40 85 19 d4 93 ff ff 00 10 00 00 00 00 00 00  .@..............\n        00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00  ................\n      backtrace:\n         seq_open+0x2a/0x80\n         full_proxy_open+0x167/0x1e0\n         do_dentry_open+0x1e1/0x3a0\n         path_openat+0x961/0xa20\n         do_filp_open+0xae/0x120\n         do_sys_openat2+0x216/0x2f0\n         do_sys_open+0x57/0x80\n         do_syscall_64+0x33/0x40\n         entry_SYSCALL_64_after_hwframe+0x44/0xa9\n    unreferenced object 0xffff93d419854000 (size 4096):\n      comm \"cat\", pid 23327, jiffies 4624670141 (age 495992.217s)\n      hex dump (first 32 bytes):\n        6b 66 65 6e 63 65 2d 23 32 35 30 3a 20 30 78 30  kfence-#250: 0x0\n        30 30 30 30 30 30 30 37 35 34 62 64 61 31 32 2d  0000000754bda12-\n      backtrace:\n         seq_read_iter+0x313/0x440\n         seq_read+0x14b/0x1a0\n         full_proxy_read+0x56/0x80\n         vfs_read+0xa5/0x1b0\n         ksys_read+0xa0/0xf0\n         do_syscall_64+0x33/0x40\n         entry_SYSCALL_64_after_hwframe+0x44/0xa9\n\nI find that we can easily reproduce this problem with the following\ncommands:\n\n\tcat /sys/kernel/debug/kfence/objects\n\techo scan > /sys/kernel/debug/kmemleak\n\tcat /sys/kernel/debug/kmemleak\n\nThe leaked memory is allocated in the stack below:\n\n    do_syscall_64\n      do_sys_open\n        do_dentry_open\n          full_proxy_open\n            seq_open            ---> alloc seq_file\n      vfs_read\n        full_proxy_read\n          seq_read\n            seq_read_iter\n              traverse          ---> alloc seq_buf\n\nAnd it should have been released in the following process:\n\n    do_syscall_64\n      syscall_exit_to_user_mode\n        exit_to_user_mode_prepare\n          task_work_run\n            ____fput\n              __fput\n                full_proxy_release  ---> free here\n\nHowever, the release function corresponding to file_operations is not\nimplemented in kfence.  As a result, a memory leak occurs.  Therefore,\nthe solution to this problem is to implement the corresponding release\nfunction."}],"affected":[{"product":"Linux","vendor":"Linux","defaultStatus":"unaffected","repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["mm/kfence/core.c"],"versions":[{"version":"0ce20dd840897b12ae70869c69f1ba34d6d16965","lessThan":"2f06c8293d27f6337f907042c602c9c953988c48","status":"affected","versionType":"git"},{"version":"0ce20dd840897b12ae70869c69f1ba34d6d16965","lessThan":"0129ab1f268b6cf88825eae819b9b84aa0a85634","status":"affected","versionType":"git"}]},{"product":"Linux","vendor":"Linux","defaultStatus":"affected","repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["mm/kfence/core.c"],"versions":[{"version":"5.12","status":"affected"},{"version":"0","lessThan":"5.12","status":"unaffected","versionType":"semver"},{"version":"5.15.12","lessThanOrEqual":"5.15.*","status":"unaffected","versionType":"semver"},{"version":"5.16","lessThanOrEqual":"*","status":"unaffected","versionType":"original_commit_for_fix"}]}],"cpeApplicability":[{"nodes":[{"operator":"OR","negate":false,"cpeMatch":[{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"5.12","versionEndExcluding":"5.15.12"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"5.12","versionEndExcluding":"5.16"}]}]}],"references":[{"url":"https://git.kernel.org/stable/c/2f06c8293d27f6337f907042c602c9c953988c48"},{"url":"https://git.kernel.org/stable/c/0129ab1f268b6cf88825eae819b9b84aa0a85634"}],"title":"kfence: fix memory leak when cat kfence objects","x_generator":{"engine":"bippy-1.2.0"}},"adp":[{"problemTypes":[{"descriptions":[{"type":"CWE","lang":"en","description":"CWE-noinfo Not enough information"}]}],"affected":[{"vendor":"linux","product":"linux_kernel","cpes":["cpe:2.3:o:linux:linux_kernel:-:*:*:*:*:*:*:*"],"defaultStatus":"unknown","versions":[{"version":"0ce20dd84089","status":"affected","lessThan":"2f06c8293d27","versionType":"custom"},{"version":"0ce20dd84089","status":"affected","lessThan":"0129ab1f268b","versionType":"custom"},{"version":"5.12","status":"affected"},{"version":"0","status":"affected","lessThan":"5.12","versionType":"custom"},{"version":"5.15.12","status":"affected","lessThanOrEqual":"5.15*","versionType":"custom"},{"version":"5.16","status":"affected","lessThanOrEqual":"*","versionType":"custom"}]}],"metrics":[{"cvssV3_1":{"scope":"UNCHANGED","version":"3.1","baseScore":3.3,"attackVector":"LOCAL","baseSeverity":"LOW","vectorString":"CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:L","integrityImpact":"NONE","userInteraction":"NONE","attackComplexity":"LOW","availabilityImpact":"LOW","privilegesRequired":"LOW","confidentialityImpact":"NONE"}},{"other":{"type":"ssvc","content":{"timestamp":"2024-10-31T13:23:25.318113Z","id":"CVE-2021-47089","options":[{"Exploitation":"none"},{"Automatable":"no"},{"Technical Impact":"total"}],"role":"CISA Coordinator","version":"2.0.3"}}}],"title":"CISA ADP Vulnrichment","providerMetadata":{"orgId":"134c704f-9b21-4f2e-91b3-4a467353bcc0","shortName":"CISA-ADP","dateUpdated":"2024-10-31T13:28:13.519Z"}},{"providerMetadata":{"orgId":"af854a3a-2127-422b-91ae-364da2661108","shortName":"CVE","dateUpdated":"2024-08-04T05:24:39.939Z"},"title":"CVE Program Container","references":[{"url":"https://git.kernel.org/stable/c/2f06c8293d27f6337f907042c602c9c953988c48","tags":["x_transferred"]},{"url":"https://git.kernel.org/stable/c/0129ab1f268b6cf88825eae819b9b84aa0a85634","tags":["x_transferred"]}]}]}}