{ "dataType": "CVE_RECORD", "dataVersion": "5.2", "cveMetadata": { "cveId": "CVE-2021-47668", "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "state": "PUBLISHED", "assignerShortName": "Linux", "dateReserved": "2025-04-16T07:16:05.752Z", "datePublished": "2025-04-17T18:01:29.315Z", "dateUpdated": "2026-08-05T08:48:48.169Z" }, "containers": { "cna": { "providerMetadata": { "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "shortName": "Linux", "dateUpdated": "2026-08-05T08:48:48.169Z" }, "descriptions": [ { "lang": "en", "value": "In the Linux kernel, the following vulnerability has been resolved:\n\ncan: dev: can_restart: fix use after free bug\n\nAfter calling netif_rx_ni(skb), dereferencing skb is unsafe.\nEspecially, the can_frame cf which aliases skb memory is accessed\nafter the netif_rx_ni() in:\n stats->rx_bytes += cf->len;\n\nReordering the lines solves the issue." } ], "metrics": [ { "cvssV3_1": { "version": "3.1", "vectorString": "CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H", "baseScore": 8.8, "baseSeverity": "HIGH" }, "scenarios": [ { "lang": "en", "value": "AV:A - The vulnerable can_restart path runs after CAN bus-off recovery on real CAN interfaces; an attacker on the same CAN segment can induce bus-off (a known CAN bus-off attack), analogous to Bluetooth/Wi‑Fi adjacent reachability rather than internet Network or host-local only.\nAC:L - Bus-off can be reliably forced from the CAN bus, and with automatic recovery (restart-ms) configured—documented and common in automotive/industrial deployments—delayed work deterministically calls can_restart; netif_rx_ni runs softirq and can_receive always frees the skb before cf->len is read.\nPR:N - An adjacent CAN attacker needs no host account or capabilities; bus-off is triggered by on-bus error conditions and the kernel schedules can_restart when restart-ms is already enabled by the deployment.\nUI:N - No victim user action is required; bus-off and subsequent automatic restart occur from attacker-driven bus errors and kernel workqueue handling alone.\nS:U - This is a kernel-context use-after-free within the same host kernel authority; it does not cross VM, IOMMU, or other security boundaries.\nC:H - Use-after-free of the CAN error skb after netif_rx_ni frees it enables reading reallocated heap contents (cf aliases skb data), which per kernel UAF guidance is High confidentiality impact.\nI:H - Kernel UAF of an sk_buff object is treated as enabling heap reuse and control-flow/corruption primitives, so Integrity is High even though the immediate buggy access is a post-free read into stats.\nA:H - Dereferencing freed skb memory can oops/panic the kernel, and any use-after-free is scored High for availability." } ] } ], "affected": [ { "product": "Linux", "vendor": "Linux", "defaultStatus": "unaffected", "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "programFiles": [ "drivers/net/can/dev.c" ], "versions": [ { "version": "39549eef3587f1c1e8c65c88a2400d10fd30ea17", "lessThan": "260925a0b7d2da5449f8ecfd02c1405e0c8a45b8", "status": "affected", "versionType": "git" }, { "version": "39549eef3587f1c1e8c65c88a2400d10fd30ea17", "lessThan": "bbc6847b9b8978b520f62fbc7c68c54ef0f8d282", "status": "affected", "versionType": "git" }, { "version": "39549eef3587f1c1e8c65c88a2400d10fd30ea17", "lessThan": "92668d28c7e6a7a2ba07df287669ffcdf650c421", "status": "affected", "versionType": "git" }, { "version": "39549eef3587f1c1e8c65c88a2400d10fd30ea17", "lessThan": "08ab951787098ae0b6c0364aeea7a8138226f234", "status": "affected", "versionType": "git" }, { "version": "39549eef3587f1c1e8c65c88a2400d10fd30ea17", "lessThan": "ac48ef15826e83f4206c47add61072e8fc76d328", "status": "affected", "versionType": "git" }, { "version": "39549eef3587f1c1e8c65c88a2400d10fd30ea17", "lessThan": "593c072b7b3c4d7044416eb039d9ad706bedd67a", "status": "affected", "versionType": "git" }, { "version": "39549eef3587f1c1e8c65c88a2400d10fd30ea17", "lessThan": "03f16c5075b22c8902d2af739969e878b0879c94", "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/dev.c" ], "versions": [ { "version": "2.6.31", "status": "affected" }, { "version": "0", "lessThan": "2.6.31", "status": "unaffected", "versionType": "semver" }, { "version": "4.4.254", "lessThanOrEqual": "4.4.*", "status": "unaffected", "versionType": "semver" }, { "version": "4.9.254", "lessThanOrEqual": "4.9.*", "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": "2.6.31", "versionEndExcluding": "4.4.254" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "2.6.31", "versionEndExcluding": "4.9.254" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "2.6.31", "versionEndExcluding": "4.14.218" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "2.6.31", "versionEndExcluding": "4.19.171" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "2.6.31", "versionEndExcluding": "5.4.93" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "2.6.31", "versionEndExcluding": "5.10.11" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "2.6.31", "versionEndExcluding": "5.11" } ] } ] } ], "references": [ { "url": "https://git.kernel.org/stable/c/260925a0b7d2da5449f8ecfd02c1405e0c8a45b8" }, { "url": "https://git.kernel.org/stable/c/bbc6847b9b8978b520f62fbc7c68c54ef0f8d282" }, { "url": "https://git.kernel.org/stable/c/92668d28c7e6a7a2ba07df287669ffcdf650c421" }, { "url": "https://git.kernel.org/stable/c/08ab951787098ae0b6c0364aeea7a8138226f234" }, { "url": "https://git.kernel.org/stable/c/ac48ef15826e83f4206c47add61072e8fc76d328" }, { "url": "https://git.kernel.org/stable/c/593c072b7b3c4d7044416eb039d9ad706bedd67a" }, { "url": "https://git.kernel.org/stable/c/03f16c5075b22c8902d2af739969e878b0879c94" } ], "title": "can: dev: can_restart: 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-2021-47668", "role": "CISA Coordinator", "options": [ { "Exploitation": "none" }, { "Automatable": "no" }, { "Technical Impact": "total" } ], "version": "2.0.3", "timestamp": "2025-04-17T18:17:56.944235Z" } } } ], "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": "2025-04-17T18:25:25.427Z" } } ] } }