{"dataType":"CVE_RECORD","dataVersion":"5.2","cveMetadata":{"cveId":"CVE-2021-47232","assignerOrgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","state":"PUBLISHED","assignerShortName":"Linux","dateReserved":"2024-04-10T18:59:19.530Z","datePublished":"2024-05-21T14:19:35.084Z","dateUpdated":"2026-08-05T08:46:51.007Z"},"containers":{"cna":{"providerMetadata":{"orgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","shortName":"Linux","dateUpdated":"2026-08-05T08:46:51.007Z"},"descriptions":[{"lang":"en","value":"In the Linux kernel, the following vulnerability has been resolved:\n\ncan: j1939: fix Use-after-Free, hold skb ref while in use\n\nThis patch fixes a Use-after-Free found by the syzbot.\n\nThe problem is that a skb is taken from the per-session skb queue,\nwithout incrementing the ref count. This leads to a Use-after-Free if\nthe skb is taken concurrently from the session queue due to a CTS."}],"metrics":[{"cvssV3_1":{"version":"3.1","vectorString":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H","baseScore":9.8,"baseSeverity":"CRITICAL"},"scenarios":[{"lang":"en","value":"AV:N - The UAF is reached via can_rcv → j1939_can_recv → j1939_tp_recv when processing peer TP.CM_CTS/DAT frames; an unauthenticated J1939/CAN peer drives the race, consistent with other packet-triggered j1939 scores (e.g. CVE-2024-56645).\nAC:L - The attacker controls CTS injection timing against an active TP session and can retry indefinitely; when both sides of the race are attacker-driven (local sockets/vcan or crafted bus traffic), success does not depend on conditions outside attacker influence.\nPR:N - J1939 receive processing has no authentication; a bus peer needs no credentials on the target, and the same path is also reachable from an unprivileged AF_CAN/CAN_J1939 socket with no capability checks on create/bind/send.\nUI:N - Frames are handled in softirq with no victim action required beyond a bound J1939 socket, which is the normal steady state on systems using this stack.\nS:U - The corrupted sk_buff and resulting privilege impact remain within the kernel's security authority; this is not a VM escape, IOMMU bypass, or sandbox boundary crossing.\nC:H - Use-after-free of the session skb enables heap grooming and arbitrary read of freed object contents (including via continued use of the dangling skb pointer in TX/RX data paths).\nI:H - The same UAF yields a reclaimable freed sk_buff that can be sprayed for arbitrary write and control-flow hijacking primitives in the kernel heap.\nA:H - Dereferencing the freed skb causes kernel oops/panic, and an unauthenticated peer can trigger the race repeatedly to deny service."}]}],"affected":[{"product":"Linux","vendor":"Linux","defaultStatus":"unaffected","repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["net/can/j1939/transport.c"],"versions":[{"version":"9d71dd0c70099914fcd063135da3c580865e924c","lessThan":"22cba878abf646cd3a02ee7c8c2cef7afe66a256","status":"affected","versionType":"git"},{"version":"9d71dd0c70099914fcd063135da3c580865e924c","lessThan":"509ab6bfdd0c76daebbad0f0af07da712116de22","status":"affected","versionType":"git"},{"version":"9d71dd0c70099914fcd063135da3c580865e924c","lessThan":"1071065eeb33d32b7d98c2ce7591881ae7381705","status":"affected","versionType":"git"},{"version":"9d71dd0c70099914fcd063135da3c580865e924c","lessThan":"2030043e616cab40f510299f09b636285e0a3678","status":"affected","versionType":"git"}]},{"product":"Linux","vendor":"Linux","defaultStatus":"affected","repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["net/can/j1939/transport.c"],"versions":[{"version":"5.4","status":"affected"},{"version":"0","lessThan":"5.4","status":"unaffected","versionType":"semver"},{"version":"5.4.128","lessThanOrEqual":"5.4.*","status":"unaffected","versionType":"semver"},{"version":"5.10.46","lessThanOrEqual":"5.10.*","status":"unaffected","versionType":"semver"},{"version":"5.12.13","lessThanOrEqual":"5.12.*","status":"unaffected","versionType":"semver"},{"version":"5.13","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":"5.4","versionEndExcluding":"5.4.128"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"5.4","versionEndExcluding":"5.10.46"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"5.4","versionEndExcluding":"5.12.13"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"5.4","versionEndExcluding":"5.13"}]}]}],"references":[{"url":"https://git.kernel.org/stable/c/22cba878abf646cd3a02ee7c8c2cef7afe66a256"},{"url":"https://git.kernel.org/stable/c/509ab6bfdd0c76daebbad0f0af07da712116de22"},{"url":"https://git.kernel.org/stable/c/1071065eeb33d32b7d98c2ce7591881ae7381705"},{"url":"https://git.kernel.org/stable/c/2030043e616cab40f510299f09b636285e0a3678"}],"title":"can: j1939: fix Use-after-Free, hold skb ref while in use","x_generator":{"engine":"bippy-1.2.0"}},"adp":[{"problemTypes":[{"descriptions":[{"type":"CWE","cweId":"CWE-416","lang":"en","description":"CWE-416 Use After Free"}]}],"affected":[{"vendor":"linux","product":"linux_kernel","cpes":["cpe:2.3:o:linux:linux_kernel:-:*:*:*:*:*:*:*"],"defaultStatus":"unknown","versions":[{"version":"9d71dd0c7009","status":"affected","lessThan":"22cba878abf6 ","versionType":"custom"}]},{"vendor":"linux","product":"linux_kernel","cpes":["cpe:2.3:o:linux:linux_kernel:-:*:*:*:*:*:*:*"],"defaultStatus":"unknown","versions":[{"version":"9d71dd0c7009","status":"affected","lessThan":" 509ab6bfdd0c ","versionType":"custom"}]},{"vendor":"linux","product":"linux_kernel","cpes":["cpe:2.3:o:linux:linux_kernel:-:*:*:*:*:*:*:*"],"defaultStatus":"unknown","versions":[{"version":"9d71dd0c7009","status":"affected","lessThan":"1071065eeb33 ","versionType":"custom"}]},{"vendor":"linux","product":"linux_kernel","cpes":["cpe:2.3:o:linux:linux_kernel:-:*:*:*:*:*:*:*"],"defaultStatus":"unknown","versions":[{"version":"9d71dd0c7009","status":"affected","lessThan":"2030043e616c ","versionType":"custom"}]},{"vendor":"linux","product":"linux_kernel","cpes":["cpe:2.3:o:linux:linux_kernel:-:*:*:*:*:*:*:*"],"defaultStatus":"unknown","versions":[{"version":"5.4.128","status":"unaffected","lessThan":"5.5","versionType":"custom"}]},{"vendor":"linux","product":"linux_kernel","cpes":["cpe:2.3:o:linux:linux_kernel:-:*:*:*:*:*:*:*"],"defaultStatus":"unknown","versions":[{"version":" 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