{ "dataType": "CVE_RECORD", "dataVersion": "5.2", "cveMetadata": { "cveId": "CVE-2021-47669", "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "state": "PUBLISHED", "assignerShortName": "Linux", "dateReserved": "2025-04-16T07:16:05.752Z", "datePublished": "2025-04-17T18:01:29.979Z", "dateUpdated": "2026-08-05T08:48:49.266Z" }, "containers": { "cna": { "providerMetadata": { "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "shortName": "Linux", "dateUpdated": "2026-08-05T08:48:49.266Z" }, "descriptions": [ { "lang": "en", "value": "In the Linux kernel, the following vulnerability has been resolved:\n\ncan: vxcan: vxcan_xmit: fix use after free bug\n\nAfter calling netif_rx_ni(skb), dereferencing skb is unsafe.\nEspecially, the canfd_frame cfd which aliases skb memory is accessed\nafter the netif_rx_ni()." } ], "metrics": [ { "cvssV3_1": { "version": "3.1", "vectorString": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H", "baseScore": 7.8, "baseSeverity": "HIGH" }, "scenarios": [ { "lang": "en", "value": "AV:L - The bug is in vxcan_xmit, reached by sending a CAN frame on a virtual vxcan interface via PF_CAN/SOCK_RAW and RTNL setup—local syscalls/netlink only, not remote packet processing.\nAC:L - netif_rx_ni() runs softirq immediately and can_receive() always consume_skb()s the delivered frame, so the post-rx cfd->len access is a reliable use-after-free with no race or uncontrolled condition.\nPR:L - Creating/bringing up vxcan requires CAP_NET_ADMIN, which an unprivileged user obtains via user+network namespaces (unshare -Urn); sending on an existing up interface needs no capability.\nUI:N - The attacker creates the vxcan pair, brings it up, and sends frames entirely on their own—no victim interaction is required.\nS:U - Impact is confined to the local kernel (memory corruption / privilege escalation within the same security authority); this is not a VM/IOMMU/sandbox boundary escape.\nC:H - This is a use-after-free of skb data after delivery; a dangling read of freed heap enables disclosure of reclaimed object contents (including via stats that incorporate the stale byte).\nI:H - Use-after-free of the skb data buffer is exploitable via heap reuse/spray for corruption and control-flow hijacking primitives beyond the immediate stats update.\nA:H - Dereferencing freed skb data can oops/panic the kernel when the page is reclaimed or unmapped, and UAF faults are reliably triggerable on the success path." } ] } ], "affected": [ { "product": "Linux", "vendor": "Linux", "defaultStatus": "unaffected", "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "programFiles": [ "drivers/net/can/vxcan.c" ], "versions": [ { "version": "a8f820a380a2a06fc4fe1a54159067958f800929", "lessThan": "6d6dcf2399cdd26f7f5426ca8dd8366b7f2ca105", "status": "affected", "versionType": "git" }, { "version": "a8f820a380a2a06fc4fe1a54159067958f800929", "lessThan": "9b820875a32a3443d67bfd368e93038354e98052", "status": "affected", "versionType": "git" }, { "version": "a8f820a380a2a06fc4fe1a54159067958f800929", "lessThan": "a24476b37167816e6352ca1a2cf3769847774f70", "status": "affected", "versionType": "git" }, { "version": "a8f820a380a2a06fc4fe1a54159067958f800929", "lessThan": "e771a874076115df8bff27d325edfd2340e4ec69", "status": "affected", "versionType": "git" }, { "version": "a8f820a380a2a06fc4fe1a54159067958f800929", "lessThan": "75854cad5d80976f6ea0f0431f8cedd3bcc475cb", "status": "affected", "versionType": "git" } ] }, { "product": "Linux", "vendor": "Linux", "defaultStatus": "affected", "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "programFiles": [ "drivers/net/can/vxcan.c" ], "versions": [ { "version": "4.12", "status": "affected" }, { "version": "0", "lessThan": "4.12", "status": "unaffected", "versionType": "semver" }, { "version": "4.14.218", "lessThanOrEqual": "4.14.*", "status": "unaffected", "versionType": "semver" }, { "version": "4.19.171", "lessThanOrEqual": "4.19.*", "status": "unaffected", "versionType": "semver" }, { "version": "5.4.93", "lessThanOrEqual": "5.4.*", "status": "unaffected", "versionType": "semver" }, { "version": "5.10.11", "lessThanOrEqual": "5.10.*", "status": "unaffected", "versionType": "semver" }, { "version": "5.11", "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": "4.12", "versionEndExcluding": "4.14.218" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "4.12", "versionEndExcluding": "4.19.171" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "4.12", "versionEndExcluding": "5.4.93" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "4.12", "versionEndExcluding": "5.10.11" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "4.12", "versionEndExcluding": "5.11" } ] } ] } ], "references": [ { "url": "https://git.kernel.org/stable/c/6d6dcf2399cdd26f7f5426ca8dd8366b7f2ca105" }, { "url": "https://git.kernel.org/stable/c/9b820875a32a3443d67bfd368e93038354e98052" }, { "url": "https://git.kernel.org/stable/c/a24476b37167816e6352ca1a2cf3769847774f70" }, { "url": "https://git.kernel.org/stable/c/e771a874076115df8bff27d325edfd2340e4ec69" }, { "url": "https://git.kernel.org/stable/c/75854cad5d80976f6ea0f0431f8cedd3bcc475cb" } ], "title": "can: vxcan: vxcan_xmit: fix use after free bug", "x_generator": { "engine": "bippy-1.2.0" } }, "adp": [ { "metrics": [ { "cvssV3_1": { "scope": "UNCHANGED", "version": "3.1", "baseScore": 7.8, "attackVector": "LOCAL", "baseSeverity": "HIGH", "vectorString": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H", "integrityImpact": "HIGH", "userInteraction": "NONE", "attackComplexity": "LOW", "availabilityImpact": "HIGH", "privilegesRequired": "LOW", "confidentialityImpact": "HIGH" } }, { "other": { "type": "ssvc", "content": { "id": "CVE-2021-47669", "role": "CISA Coordinator", "options": [ { "Exploitation": "none" }, { "Automatable": "no" }, { "Technical Impact": "total" } ], "version": "2.0.3", "timestamp": "2025-04-17T18:17:52.149604Z" } } } ], "problemTypes": [ { "descriptions": [ { "lang": "en", "type": "CWE", "cweId": "CWE-416", "description": "CWE-416 Use After Free" } ] } ], "title": "CISA ADP Vulnrichment", "providerMetadata": { "orgId": "134c704f-9b21-4f2e-91b3-4a467353bcc0", "shortName": "CISA-ADP", "dateUpdated": "2025-04-17T18:25:25.277Z" } } ] } }