{"id":"CVE-2021-47231","state":"PUBLISHED","title":"can: mcba_usb: fix memory leak in mcba_usb","description":"In the Linux kernel, the following vulnerability has been resolved:\n\ncan: mcba_usb: fix memory leak in mcba_usb\n\nSyzbot reported memory leak in SocketCAN driver for Microchip CAN BUS\nAnalyzer Tool. The problem was in unfreed usb_coherent.\n\nIn mcba_usb_start() 20 coherent buffers are allocated and there is\nnothing, that frees them:\n\n1) In callback function the urb is resubmitted and that's all\n2) In disconnect function urbs are simply killed, but URB_FREE_BUFFER\n   is not set (see mcba_usb_start) and this flag cannot be used with\n   coherent buffers.\n\nFail log:\n| [ 1354.053291][ T8413] mcba_usb 1-1:0.0 can0: device disconnected\n| [ 1367.059384][ T8420] kmemleak: 20 new suspected memory leaks (see /sys/kernel/debug/kmem)\n\nSo, all allocated buffers should be freed with usb_free_coherent()\nexplicitly\n\nNOTE:\nThe same pattern for allocating and freeing coherent buffers\nis used in drivers/net/can/usb/kvaser_usb/kvaser_usb_core.c","publishedAt":"2024-05-21T14:19:34.413Z","updatedAt":"2026-05-11T13:50:29.828Z","severity":{"score":5.5,"label":"Medium","version":"3.1","vector":"CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H","source":"CISA-ADP"},"assigner":"Linux","products":["Linux Linux"],"affected":[{"vendor":"Linux","product":"Linux","defaultStatus":"unaffected","versions":[{"version":"51f3baad7de943780ce0c17bd7975df567dd6e14","status":"affected","lessThan":"89df95ce32be204eef2e7d4b2f6fb552fb191a68","versionType":"git"},{"version":"51f3baad7de943780ce0c17bd7975df567dd6e14","status":"affected","lessThan":"a115198caaab6d663bef75823a3c5f0802306d60","versionType":"git"},{"version":"51f3baad7de943780ce0c17bd7975df567dd6e14","status":"affected","lessThan":"6f87c0e21ad20dd3d22108e33db1c552dfa352a0","versionType":"git"},{"version":"51f3baad7de943780ce0c17bd7975df567dd6e14","status":"affected","lessThan":"6bd3d80d1f019cefa7011056c54b323f1d8b8e83","versionType":"git"},{"version":"51f3baad7de943780ce0c17bd7975df567dd6e14","status":"affected","lessThan":"d0760a4ef85697bc756d06eae17ae27f3f055401","versionType":"git"},{"version":"51f3baad7de943780ce0c17bd7975df567dd6e14","status":"affected","lessThan":"91c02557174be7f72e46ed7311e3bea1939840b0","versionType":"git"}],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["drivers/net/can/usb/mcba_usb.c"]},{"vendor":"Linux","product":"Linux","defaultStatus":"affected","versions":[{"version":"4.12","status":"affected"},{"version":"0","status":"unaffected","lessThan":"4.12","versionType":"semver"},{"version":"4.14.238","status":"unaffected","lessThanOrEqual":"4.14.*","versionType":"semver"},{"version":"4.19.196","status":"unaffected","lessThanOrEqual":"4.19.*","versionType":"semver"},{"version":"5.4.128","status":"unaffected","lessThanOrEqual":"5.4.*","versionType":"semver"},{"version":"5.10.46","status":"unaffected","lessThanOrEqual":"5.10.*","versionType":"semver"},{"version":"5.12.13","status":"unaffected","lessThanOrEqual":"5.12.*","versionType":"semver"},{"version":"5.13","status":"unaffected","lessThanOrEqual":"*","versionType":"original_commit_for_fix"}],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["drivers/net/can/usb/mcba_usb.c"]}],"references":["https://git.kernel.org/stable/c/89df95ce32be204eef2e7d4b2f6fb552fb191a68","https://git.kernel.org/stable/c/a115198caaab6d663bef75823a3c5f0802306d60","https://git.kernel.org/stable/c/6f87c0e21ad20dd3d22108e33db1c552dfa352a0","https://git.kernel.org/stable/c/6bd3d80d1f019cefa7011056c54b323f1d8b8e83","https://git.kernel.org/stable/c/d0760a4ef85697bc756d06eae17ae27f3f055401","https://git.kernel.org/stable/c/91c02557174be7f72e46ed7311e3bea1939840b0"],"weaknesses":[],"ingestedAt":"2026-10-29T19:49:19.404Z","source":{"repository":"CVEProject/cvelistV5","path":"cves/2021/47xxx/CVE-2021-47231.json","commit":"556c9d3a8cd17e218bb8e452ba7cd619a384ff47"},"raw":{"dataType":"CVE_RECORD","dataVersion":"5.2","cveMetadata":{"cveId":"CVE-2021-47231","state":"PUBLISHED","datePublished":"2024-05-21T14:19:34.413Z","dateUpdated":"2026-05-11T13:50:29.828Z","assignerShortName":"Linux","assignerOrgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","dateReserved":"2024-04-10T18:59:19.530Z"},"containers":{"cna":{"title":"can: mcba_usb: fix memory leak in mcba_usb","descriptions":[{"lang":"en","value":"In the Linux kernel, the following vulnerability has been resolved:\n\ncan: mcba_usb: fix memory leak in mcba_usb\n\nSyzbot reported memory leak in SocketCAN driver for Microchip CAN BUS\nAnalyzer Tool. The problem was in unfreed usb_coherent.\n\nIn mcba_usb_start() 20 coherent buffers are allocated and there is\nnothing, that frees them:\n\n1) In callback function the urb is resubmitted and that's all\n2) In disconnect function urbs are simply killed, but URB_FREE_BUFFER\n   is not set (see mcba_usb_start) and this flag cannot be used with\n   coherent buffers.\n\nFail log:\n| [ 1354.053291][ T8413] mcba_usb 1-1:0.0 can0: device disconnected\n| [ 1367.059384][ T8420] kmemleak: 20 new suspected memory leaks (see /sys/kernel/debug/kmem)\n\nSo, all allocated buffers should be freed with usb_free_coherent()\nexplicitly\n\nNOTE:\nThe same pattern for allocating and freeing coherent buffers\nis used in 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