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CVE-2021-47089 (GCVE-0-2021-47089)

Vulnerability from cvelistv5 – Published: 2024-03-04 18:10 – Updated: 2026-05-11 13:47
VLAI
Title
kfence: fix memory leak when cat kfence objects
Summary
In the Linux kernel, the following vulnerability has been resolved: kfence: fix memory leak when cat kfence objects Hulk robot reported a kmemleak problem: unreferenced object 0xffff93d1d8cc02e8 (size 248): comm "cat", pid 23327, jiffies 4624670141 (age 495992.217s) hex dump (first 32 bytes): 00 40 85 19 d4 93 ff ff 00 10 00 00 00 00 00 00 .@.............. 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................ backtrace: seq_open+0x2a/0x80 full_proxy_open+0x167/0x1e0 do_dentry_open+0x1e1/0x3a0 path_openat+0x961/0xa20 do_filp_open+0xae/0x120 do_sys_openat2+0x216/0x2f0 do_sys_open+0x57/0x80 do_syscall_64+0x33/0x40 entry_SYSCALL_64_after_hwframe+0x44/0xa9 unreferenced object 0xffff93d419854000 (size 4096): comm "cat", pid 23327, jiffies 4624670141 (age 495992.217s) hex dump (first 32 bytes): 6b 66 65 6e 63 65 2d 23 32 35 30 3a 20 30 78 30 kfence-#250: 0x0 30 30 30 30 30 30 30 37 35 34 62 64 61 31 32 2d 0000000754bda12- backtrace: seq_read_iter+0x313/0x440 seq_read+0x14b/0x1a0 full_proxy_read+0x56/0x80 vfs_read+0xa5/0x1b0 ksys_read+0xa0/0xf0 do_syscall_64+0x33/0x40 entry_SYSCALL_64_after_hwframe+0x44/0xa9 I find that we can easily reproduce this problem with the following commands: cat /sys/kernel/debug/kfence/objects echo scan > /sys/kernel/debug/kmemleak cat /sys/kernel/debug/kmemleak The leaked memory is allocated in the stack below: do_syscall_64 do_sys_open do_dentry_open full_proxy_open seq_open ---> alloc seq_file vfs_read full_proxy_read seq_read seq_read_iter traverse ---> alloc seq_buf And it should have been released in the following process: do_syscall_64 syscall_exit_to_user_mode exit_to_user_mode_prepare task_work_run ____fput __fput full_proxy_release ---> free here However, the release function corresponding to file_operations is not implemented in kfence. As a result, a memory leak occurs. Therefore, the solution to this problem is to implement the corresponding release function.
Severity
3.3 (Low)
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:L
SSVC
Exploitation: none Automatable: no Technical Impact: total
CISA Coordinator · CISA-ADP (v2.0.3)
Decision recorded 2024-10-31 13:23 UTC
CWE
Assigner
References
Impacted products
Vendor Product Version CPE status
Linux Linux Affected: 0ce20dd840897b12ae70869c69f1ba34d6d16965 , < 2f06c8293d27f6337f907042c602c9c953988c48 (git)
Affected: 0ce20dd840897b12ae70869c69f1ba34d6d16965 , < 0129ab1f268b6cf88825eae819b9b84aa0a85634 (git)
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Linux Linux Affected: 5.12
Unaffected: 0 , < 5.12 (semver)
Unaffected: 5.15.12 , ≤ 5.15.* (semver)
Unaffected: 5.16 , ≤ * (original_commit_for_fix)
guessed Create a notification for this product.
linux linux_kernel Affected: 0ce20dd84089 , < 2f06c8293d27 (custom)
Affected: 0ce20dd84089 , < 0129ab1f268b (custom)
Affected: 5.12
Affected: 0 , < 5.12 (custom)
Affected: 5.15.12 , ≤ 5.15* (custom)
Affected: 5.16 , ≤ * (custom)
    cpe:2.3:o:linux:linux_kernel:-:*:*:*:*:*:*:*
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          "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 \u003e /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            ---\u003e alloc seq_file\n      vfs_read\n        full_proxy_read\n          seq_read\n            seq_read_iter\n              traverse          ---\u003e 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  ---\u003e 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."
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    "fkie_nvd": {
      "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 \u003e /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            ---\u003e alloc seq_file\\n      vfs_read\\n        full_proxy_read\\n          seq_read\\n            seq_read_iter\\n              traverse          ---\u003e 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  ---\u003e 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.\"}, {\"lang\": \"es\", \"value\": \"En el kernel de Linux, se ha resuelto la siguiente vulnerabilidad: kfence: repara la p\\u00e9rdida de memoria cuando los objetos cat kfence Hulk robot inform\\u00f3 un problema kmemleak: objeto sin referencia 0xffff93d1d8cc02e8 (tama\\u00f1o 248): comm \\\"cat\\\", pid 23327, jiffies 4624670141 (edad 495992.217s ) volcado hexadecimal (primeros 32 bytes): 00 40 85 19 d4 93 ff ff 00 10 00 00 00 00 00 00 .@.............. 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................. rastreo inverso: seq_open+0x2a/0x80 full_proxy_open+0x167/0x1e0 do_dentry_open+0x1e1/0x3a0 path_openat+0x961/0xa20 do_filp_open+0xae/0x120 do_sys_openat2+0x216/0x2f0 do_sys_open+0x57/0x80 do_syscall_64+0x33/0x40 Entry_SYSCALL_64_after_hwframe+0x44/0xa9 objeto sin referencia 0xffff93d419854000 (tama\\u00f1o 4096): comm \\\"cat\\\", pid 23327, Jiffies 4624670141 (edad 495992,217 s) volcado hexadecimal (primeros 32 bytes) : 6b 66 65 6e 63 65 2d 23 32 35 30 3a 20 30 78 30 kfence-#250: 0x0 30 30 30 30 30 30 30 37 35 34 62 64 61 31 32 2d 0000000754bda1 2- rastreo inverso: seq_read_iter+0x313/0x440 seq_read+ 0x14b/0x1a0 full_proxy_read+0x56/0x80 vfs_read+0xa5/0x1b0 ksys_read+0xa0/0xf0 do_syscall_64+0x33/0x40 Entry_SYSCALL_64_after_hwframe+0x44/0xa9 Creo que podemos reproducir f\\u00e1cilmente este problema con los siguientes comandos: cat /sys/kernel/ depurar/ kfence/objects echo scan \u0026gt; /sys/kernel/debug/kmemleak cat /sys/kernel/debug/kmemleak La memoria filtrada se asigna en la pila siguiente: do_syscall_64 do_sys_open do_dentry_open full_proxy_open seq_open ---\u0026gt; alloc seq_file vfs_read full_proxy_read seq_read seq_read_iter traverse - --\u0026gt; alloc seq_buf Y deber\\u00eda haberse liberado en el siguiente proceso: do_syscall_64 syscall_exit_to_user_mode exit_to_user_mode_prepare task_work_run ____fput __fput full_proxy_release ---\u0026gt; free aqu\\u00ed Sin embargo, la funci\\u00f3n de liberaci\\u00f3n correspondiente a file_operatives no est\\u00e1 implementada en kfence. Como resultado, se produce una p\\u00e9rdida de memoria. Por tanto, la soluci\\u00f3n a este problema es implementar la funci\\u00f3n de liberaci\\u00f3n correspondiente.\"}]",
      "id": "CVE-2021-47089",
      "lastModified": "2024-11-21T06:35:22.480",
      "metrics": "{\"cvssMetricV31\": [{\"source\": \"134c704f-9b21-4f2e-91b3-4a467353bcc0\", \"type\": \"Secondary\", \"cvssData\": {\"version\": \"3.1\", \"vectorString\": \"CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:L\", \"baseScore\": 3.3, \"baseSeverity\": \"LOW\", \"attackVector\": \"LOCAL\", \"attackComplexity\": \"LOW\", \"privilegesRequired\": \"LOW\", \"userInteraction\": \"NONE\", \"scope\": \"UNCHANGED\", \"confidentialityImpact\": \"NONE\", \"integrityImpact\": \"NONE\", \"availabilityImpact\": \"LOW\"}, \"exploitabilityScore\": 1.8, \"impactScore\": 1.4}]}",
      "published": "2024-03-04T18:15:07.560",
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      "sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "vulnStatus": "Awaiting Analysis"
    },
    "nvd": "{\"cve\":{\"id\":\"CVE-2021-47089\",\"sourceIdentifier\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\",\"published\":\"2024-03-04T18:15:07.560\",\"lastModified\":\"2026-06-17T04:16:26.517\",\"vulnStatus\":\"Analyzed\",\"cveTags\":[],\"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 \u003e /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            ---\u003e alloc seq_file\\n      vfs_read\\n        full_proxy_read\\n          seq_read\\n            seq_read_iter\\n              traverse          ---\u003e 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  ---\u003e 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.\"},{\"lang\":\"es\",\"value\":\"En el kernel de Linux, se ha resuelto la siguiente vulnerabilidad: kfence: repara la p\u00e9rdida de memoria cuando los objetos cat kfence Hulk robot inform\u00f3 un problema kmemleak: objeto sin referencia 0xffff93d1d8cc02e8 (tama\u00f1o 248): comm \\\"cat\\\", pid 23327, jiffies 4624670141 (edad 495992.217s ) volcado hexadecimal (primeros 32 bytes): 00 40 85 19 d4 93 ff ff 00 10 00 00 00 00 00 00 .@.............. 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................. rastreo inverso: seq_open+0x2a/0x80 full_proxy_open+0x167/0x1e0 do_dentry_open+0x1e1/0x3a0 path_openat+0x961/0xa20 do_filp_open+0xae/0x120 do_sys_openat2+0x216/0x2f0 do_sys_open+0x57/0x80 do_syscall_64+0x33/0x40 Entry_SYSCALL_64_after_hwframe+0x44/0xa9 objeto sin referencia 0xffff93d419854000 (tama\u00f1o 4096): comm \\\"cat\\\", pid 23327, Jiffies 4624670141 (edad 495992,217 s) volcado hexadecimal (primeros 32 bytes) : 6b 66 65 6e 63 65 2d 23 32 35 30 3a 20 30 78 30 kfence-#250: 0x0 30 30 30 30 30 30 30 37 35 34 62 64 61 31 32 2d 0000000754bda1 2- rastreo inverso: seq_read_iter+0x313/0x440 seq_read+ 0x14b/0x1a0 full_proxy_read+0x56/0x80 vfs_read+0xa5/0x1b0 ksys_read+0xa0/0xf0 do_syscall_64+0x33/0x40 Entry_SYSCALL_64_after_hwframe+0x44/0xa9 Creo que podemos reproducir f\u00e1cilmente este problema con los siguientes comandos: cat /sys/kernel/ depurar/ kfence/objects echo scan \u0026gt; /sys/kernel/debug/kmemleak cat /sys/kernel/debug/kmemleak La memoria filtrada se asigna en la pila siguiente: do_syscall_64 do_sys_open do_dentry_open full_proxy_open seq_open ---\u0026gt; alloc seq_file vfs_read full_proxy_read seq_read seq_read_iter traverse - --\u0026gt; alloc seq_buf Y deber\u00eda haberse liberado en el siguiente proceso: do_syscall_64 syscall_exit_to_user_mode exit_to_user_mode_prepare task_work_run ____fput __fput full_proxy_release ---\u0026gt; free aqu\u00ed Sin embargo, la funci\u00f3n de liberaci\u00f3n correspondiente a file_operatives no est\u00e1 implementada en kfence. Como resultado, se produce una p\u00e9rdida de memoria. Por tanto, la soluci\u00f3n a este problema es implementar la funci\u00f3n de liberaci\u00f3n correspondiente.\"}],\"affected\":[{\"source\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\",\"affectedData\":[{\"vendor\":\"Linux\",\"product\":\"Linux\",\"defaultStatus\":\"unaffected\",\"programFiles\":[\"mm/kfence/core.c\"],\"repo\":\"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git\",\"versions\":[{\"version\":\"0ce20dd840897b12ae70869c69f1ba34d6d16965\",\"lessThan\":\"2f06c8293d27f6337f907042c602c9c953988c48\",\"versionType\":\"git\",\"status\":\"affected\"},{\"version\":\"0ce20dd840897b12ae70869c69f1ba34d6d16965\",\"lessThan\":\"0129ab1f268b6cf88825eae819b9b84aa0a85634\",\"versionType\":\"git\",\"status\":\"affected\"}]},{\"vendor\":\"Linux\",\"product\":\"Linux\",\"defaultStatus\":\"affected\",\"programFiles\":[\"mm/kfence/core.c\"],\"repo\":\"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git\",\"versions\":[{\"version\":\"5.12\",\"status\":\"affected\"},{\"version\":\"0\",\"lessThan\":\"5.12\",\"versionType\":\"semver\",\"status\":\"unaffected\"},{\"version\":\"5.15.12\",\"lessThanOrEqual\":\"5.15.*\",\"versionType\":\"semver\",\"status\":\"unaffected\"},{\"version\":\"5.16\",\"lessThanOrEqual\":\"*\",\"versionType\":\"original_commit_for_fix\",\"status\":\"unaffected\"}]}]},{\"source\":\"134c704f-9b21-4f2e-91b3-4a467353bcc0\",\"affectedData\":[{\"vendor\":\"linux\",\"product\":\"linux_kernel\",\"defaultStatus\":\"unknown\",\"cpes\":[\"cpe:2.3:o:linux:linux_kernel:-:*:*:*:*:*:*:*\"],\"versions\":[{\"version\":\"0ce20dd84089\",\"lessThan\":\"2f06c8293d27\",\"versionType\":\"custom\",\"status\":\"affected\"},{\"version\":\"0ce20dd84089\",\"lessThan\":\"0129ab1f268b\",\"versionType\":\"custom\",\"status\":\"affected\"},{\"version\":\"5.12\",\"status\":\"affected\"},{\"version\":\"0\",\"lessThan\":\"5.12\",\"versionType\":\"custom\",\"status\":\"affected\"},{\"version\":\"5.15.12\",\"lessThanOrEqual\":\"5.15*\",\"versionType\":\"custom\",\"status\":\"affected\"},{\"version\":\"5.16\",\"lessThanOrEqual\":\"*\",\"versionType\":\"custom\",\"status\":\"affected\"}]}]}],\"metrics\":{\"cvssMetricV31\":[{\"source\":\"134c704f-9b21-4f2e-91b3-4a467353bcc0\",\"type\":\"Secondary\",\"cvssData\":{\"version\":\"3.1\",\"vectorString\":\"CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:L\",\"baseScore\":3.3,\"baseSeverity\":\"LOW\",\"attackVector\":\"LOCAL\",\"attackComplexity\":\"LOW\",\"privilegesRequired\":\"LOW\",\"userInteraction\":\"NONE\",\"scope\":\"UNCHANGED\",\"confidentialityImpact\":\"NONE\",\"integrityImpact\":\"NONE\",\"availabilityImpact\":\"LOW\"},\"exploitabilityScore\":1.8,\"impactScore\":1.4}],\"ssvcV203\":[{\"source\":\"134c704f-9b21-4f2e-91b3-4a467353bcc0\",\"ssvcData\":{\"timestamp\":\"2024-10-31T13:23:25.318113Z\",\"id\":\"CVE-2021-47089\",\"options\":[{\"exploitation\":\"none\"},{\"automatable\":\"no\"},{\"technicalImpact\":\"total\"}],\"role\":\"CISA Coordinator\",\"version\":\"2.0.3\"}}]},\"weaknesses\":[{\"source\":\"nvd@nist.gov\",\"type\":\"Primary\",\"description\":[{\"lang\":\"en\",\"value\":\"CWE-401\"}]}],\"configurations\":[{\"nodes\":[{\"operator\":\"OR\",\"negate\":false,\"cpeMatch\":[{\"vulnerable\":true,\"criteria\":\"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*\",\"versionStartIncluding\":\"5.12\",\"versionEndExcluding\":\"5.15.12\",\"matchCriteriaId\":\"5CAD6D48-E560-4E57-93BC-36BEBD6A8FA6\"},{\"vulnerable\":true,\"criteria\":\"cpe:2.3:o:linux:linux_kernel:5.16:rc1:*:*:*:*:*:*\",\"matchCriteriaId\":\"357AA433-37E8-4323-BFB2-3038D6E4B414\"},{\"vulnerable\":true,\"criteria\":\"cpe:2.3:o:linux:linux_kernel:5.16:rc2:*:*:*:*:*:*\",\"matchCriteriaId\":\"A73429BA-C2D9-4D0C-A75F-06A1CA8B3983\"},{\"vulnerable\":true,\"criteria\":\"cpe:2.3:o:linux:linux_kernel:5.16:rc3:*:*:*:*:*:*\",\"matchCriteriaId\":\"F621B5E3-E99D-49E7-90B9-EC3B77C95383\"},{\"vulnerable\":true,\"criteria\":\"cpe:2.3:o:linux:linux_kernel:5.16:rc4:*:*:*:*:*:*\",\"matchCriteriaId\":\"F7BFDCAA-1650-49AA-8462-407DD593F94F\"},{\"vulnerable\":true,\"criteria\":\"cpe:2.3:o:linux:linux_kernel:5.16:rc5:*:*:*:*:*:*\",\"matchCriteriaId\":\"6EC9882F-866D-4ACB-8FBC-213D8D8436C8\"},{\"vulnerable\":true,\"criteria\":\"cpe:2.3:o:linux:linux_kernel:5.16:rc6:*:*:*:*:*:*\",\"matchCriteriaId\":\"8A0915FE-A4AA-4C94-B783-CF29D81E7E54\"}]}]}],\"references\":[{\"url\":\"https://git.kernel.org/stable/c/0129ab1f268b6cf88825eae819b9b84aa0a85634\",\"source\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\",\"tags\":[\"Patch\"]},{\"url\":\"https://git.kernel.org/stable/c/2f06c8293d27f6337f907042c602c9c953988c48\",\"source\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\",\"tags\":[\"Patch\"]},{\"url\":\"https://git.kernel.org/stable/c/0129ab1f268b6cf88825eae819b9b84aa0a85634\",\"source\":\"af854a3a-2127-422b-91ae-364da2661108\",\"tags\":[\"Patch\"]},{\"url\":\"https://git.kernel.org/stable/c/2f06c8293d27f6337f907042c602c9c953988c48\",\"source\":\"af854a3a-2127-422b-91ae-364da2661108\",\"tags\":[\"Patch\"]}]}}",
    "redhat_vex": {
      "aggregate_severity": "Low",
      "current_release_date": "2025-11-21T14:43:14+00:00",
      "cve": "CVE-2021-47089",
      "id": "CVE-2021-47089",
      "initial_release_date": "2021-01-01T00:00:00+00:00",
      "product_status:known_affected": "108",
      "product_status:known_not_affected": "90",
      "source": "Red Hat CSAF VEX",
      "status": "final",
      "title": "kernel: kfence: fix memory leak when cat kfence objects",
      "url": "https://security.access.redhat.com/data/csaf/v2/vex/2021/cve-2021-47089.json",
      "version": "3"
    },
    "suse_vex": {
      "aggregate_severity": "moderate",
      "current_release_date": "2026-09-11T16:59:24Z",
      "cve": "CVE-2021-47089",
      "id": "CVE-2021-47089",
      "initial_release_date": "2024-03-06T04:52:29Z",
      "product_status:known_affected": "330",
      "product_status:known_not_affected": "342",
      "product_status:recommended": "298",
      "source": "SUSE CSAF VEX",
      "status": "interim",
      "title": "SUSE CVE CVE-2021-47089",
      "url": "https://ftp.suse.com/pub/projects/security/csaf-vex/cve-2021-47089.json",
      "version": "63"
    },
    "vulnrichment": {
      "containers": "{\"adp\": [{\"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\"]}], \"providerMetadata\": {\"orgId\": \"af854a3a-2127-422b-91ae-364da2661108\", \"shortName\": \"CVE\", \"dateUpdated\": \"2024-08-04T05:24:39.939Z\"}}, {\"title\": \"CISA ADP Vulnrichment\", \"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\": {\"id\": \"CVE-2021-47089\", \"role\": \"CISA Coordinator\", \"options\": [{\"Exploitation\": \"none\"}, {\"Automatable\": \"no\"}, {\"Technical Impact\": \"total\"}], \"version\": \"2.0.3\", \"timestamp\": \"2024-10-31T13:23:25.318113Z\"}}}], \"affected\": [{\"cpes\": [\"cpe:2.3:o:linux:linux_kernel:-:*:*:*:*:*:*:*\"], \"vendor\": \"linux\", \"product\": \"linux_kernel\", \"versions\": [{\"status\": \"affected\", \"version\": \"0ce20dd84089\", \"lessThan\": \"2f06c8293d27\", \"versionType\": \"custom\"}, {\"status\": \"affected\", \"version\": \"0ce20dd84089\", \"lessThan\": \"0129ab1f268b\", \"versionType\": \"custom\"}, {\"status\": \"affected\", \"version\": \"5.12\"}, {\"status\": \"affected\", \"version\": \"0\", \"lessThan\": \"5.12\", \"versionType\": \"custom\"}, {\"status\": \"affected\", \"version\": \"5.15.12\", \"versionType\": \"custom\", \"lessThanOrEqual\": \"5.15*\"}, {\"status\": \"affected\", \"version\": \"5.16\", \"versionType\": \"custom\", \"lessThanOrEqual\": \"*\"}], \"defaultStatus\": \"unknown\"}], \"problemTypes\": [{\"descriptions\": [{\"lang\": \"en\", \"type\": \"CWE\", \"description\": \"CWE-noinfo Not enough information\"}]}], \"providerMetadata\": {\"orgId\": \"134c704f-9b21-4f2e-91b3-4a467353bcc0\", \"shortName\": \"CISA-ADP\", \"dateUpdated\": \"2024-07-24T14:25:51.167Z\"}}], \"cna\": {\"title\": \"kfence: fix memory leak when cat kfence objects\", \"affected\": [{\"repo\": \"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git\", \"vendor\": \"Linux\", \"product\": \"Linux\", \"versions\": [{\"status\": \"affected\", \"version\": \"0ce20dd840897b12ae70869c69f1ba34d6d16965\", \"lessThan\": \"2f06c8293d27f6337f907042c602c9c953988c48\", \"versionType\": \"git\"}, {\"status\": \"affected\", \"version\": \"0ce20dd840897b12ae70869c69f1ba34d6d16965\", \"lessThan\": \"0129ab1f268b6cf88825eae819b9b84aa0a85634\", \"versionType\": \"git\"}], \"programFiles\": [\"mm/kfence/core.c\"], \"defaultStatus\": \"unaffected\"}, {\"repo\": \"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git\", \"vendor\": \"Linux\", \"product\": \"Linux\", \"versions\": [{\"status\": \"affected\", \"version\": \"5.12\"}, {\"status\": \"unaffected\", \"version\": \"0\", \"lessThan\": \"5.12\", \"versionType\": \"semver\"}, {\"status\": \"unaffected\", \"version\": \"5.15.12\", \"versionType\": \"semver\", \"lessThanOrEqual\": \"5.15.*\"}, {\"status\": \"unaffected\", \"version\": \"5.16\", \"versionType\": \"original_commit_for_fix\", \"lessThanOrEqual\": \"*\"}], \"programFiles\": [\"mm/kfence/core.c\"], \"defaultStatus\": \"affected\"}], \"references\": [{\"url\": \"https://git.kernel.org/stable/c/2f06c8293d27f6337f907042c602c9c953988c48\"}, {\"url\": \"https://git.kernel.org/stable/c/0129ab1f268b6cf88825eae819b9b84aa0a85634\"}], \"x_generator\": {\"engine\": \"bippy-1.2.0\"}, \"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 \u003e /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            ---\u003e alloc seq_file\\n      vfs_read\\n        full_proxy_read\\n          seq_read\\n            seq_read_iter\\n              traverse          ---\u003e 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  ---\u003e 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.\"}], \"cpeApplicability\": [{\"nodes\": [{\"negate\": false, \"cpeMatch\": [{\"criteria\": \"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*\", \"vulnerable\": true, \"versionEndExcluding\": \"5.15.12\", \"versionStartIncluding\": \"5.12\"}, {\"criteria\": \"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*\", \"vulnerable\": true, \"versionEndExcluding\": \"5.16\", \"versionStartIncluding\": \"5.12\"}], \"operator\": \"OR\"}]}], \"providerMetadata\": {\"orgId\": \"416baaa9-dc9f-4396-8d5f-8c081fb06d67\", \"shortName\": \"Linux\", \"dateUpdated\": \"2025-05-04T07:03:54.349Z\"}}}",
      "cveMetadata": "{\"cveId\": \"CVE-2021-47089\", \"state\": \"PUBLISHED\", \"dateUpdated\": \"2025-05-04T07:03:54.349Z\", \"dateReserved\": \"2024-02-29T22:33:44.300Z\", \"assignerOrgId\": \"416baaa9-dc9f-4396-8d5f-8c081fb06d67\", \"datePublished\": \"2024-03-04T18:10:27.495Z\", \"assignerShortName\": \"Linux\"}",
      "dataType": "CVE_RECORD",
      "dataVersion": "5.1"
    }
  }
}



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Forecast uses a logistic model when the trend is rising, or an exponential decay model when the trend is falling. Fitted via linearized least squares.

Sightings

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Nomenclature

  • Seen: The vulnerability was mentioned, discussed, or observed by the user.
  • Confirmed: The vulnerability has been validated from an analyst's perspective.
  • Published Proof of Concept: A public proof of concept is available for this vulnerability.
  • Exploited: The vulnerability was observed as exploited by the user who reported the sighting.
  • Patched: The vulnerability was observed as successfully patched by the user who reported the sighting.
  • Not exploited: The vulnerability was not observed as exploited by the user who reported the sighting.
  • Not confirmed: The user expressed doubt about the validity of the vulnerability.
  • Not patched: The vulnerability was not observed as successfully patched by the user who reported the sighting.


Detection rules are retrieved from Rulezet.


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Vulnerabilities whose description is nearest to this one in the vector space of the CIRCL/vulnerability-attack-technique-biencoder model. This is a similarity search over the bi-encoder space (plain cosine), not a classification, and it has no measured accuracy.