{ "dataType": "CVE_RECORD", "dataVersion": "5.2", "cveMetadata": { "cveId": "CVE-2021-47520", "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "state": "PUBLISHED", "assignerShortName": "Linux", "dateReserved": "2024-05-24T15:02:54.824Z", "datePublished": "2024-05-24T15:09:33.796Z", "dateUpdated": "2026-08-05T08:48:14.519Z" }, "containers": { "cna": { "providerMetadata": { "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "shortName": "Linux", "dateUpdated": "2026-08-05T08:48:14.519Z" }, "descriptions": [ { "lang": "en", "value": "In the Linux kernel, the following vulnerability has been resolved:\n\ncan: pch_can: pch_can_rx_normal: fix use after free\n\nAfter calling netif_receive_skb(skb), dereferencing skb is unsafe.\nEspecially, the can_frame cf which aliases skb memory is dereferenced\njust after the call netif_receive_skb(skb).\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 UAF is in the pch_can hardware RX path (PCI interrupt → NAPI → pch_can_rx_normal), triggered by Classical CAN frames arriving on the shared CAN bus; like Bluetooth/WiFi this is limited to the same physical bus segment, not Internet-routable.\nAC:L - Any received frame reliably hits the bug: can_receive() always consume_skb()s the original skb after delivery, so cf (aliasing skb data) is always dangling when cf->len is read; the attacker fully controls frame injection on the bus.\nPR:N - Exploitation requires only the ability to inject unauthenticated CAN frames onto the bus attached to the EG20T PCH controller; no local account or capability on the victim Linux system is needed.\nUI:N - No victim action is required beyond the CAN interface already being operational and receiving, which is the normal deployed state for this controller.\nS:U - Impact is confined to the local kernel's networking/stats path; there is no VM escape, IOMMU bypass, or other cross-authority boundary crossing.\nC:H - This is a use-after-free of skb/can_frame memory after netif_receive_skb; UAF of freed heap objects can be leveraged for information disclosure (including via the cf->len read into observable rx_bytes stats).\nI:H - Use-after-free of the skb backing store enables heap reuse/spray primitives that can be escalated to integrity compromise and control-flow hijacking under standard kernel UAF exploitation models.\nA:H - The deterministic UAF on every RX frame can cause kernel oops/panic (e.g. under KASAN or when the reclaimed page is unmapped), fully disrupting the system." } ] } ], "affected": [ { "product": "Linux", "vendor": "Linux", "defaultStatus": "unaffected", "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "programFiles": [ "drivers/net/can/pch_can.c" ], "versions": [ { "version": "b21d18b51b31a24d17f883b678432fbdee3d5675", "lessThan": "bafe343a885c70dddf358379cf0b2a1c07355d8d", "status": "affected", "versionType": "git" }, { "version": "b21d18b51b31a24d17f883b678432fbdee3d5675", "lessThan": "3a3c46e2eff0577454860a203be1a8295f4acb76", "status": "affected", "versionType": "git" }, { "version": "b21d18b51b31a24d17f883b678432fbdee3d5675", "lessThan": "affbad02bf80380a7403885b9fe4a1587d1bb4f3", "status": "affected", "versionType": "git" }, { "version": "b21d18b51b31a24d17f883b678432fbdee3d5675", "lessThan": "3e193ef4e0a3f5bf92ede83ef214cb09d01b00aa", "status": "affected", "versionType": "git" }, { "version": "b21d18b51b31a24d17f883b678432fbdee3d5675", "lessThan": "abb4eff3dcd2e583060082a18a8dbf31f02689d4", "status": "affected", "versionType": "git" }, { "version": "b21d18b51b31a24d17f883b678432fbdee3d5675", "lessThan": "703dde112021c93d6e89443c070e7dbd4dea612e", "status": "affected", "versionType": "git" }, { "version": "b21d18b51b31a24d17f883b678432fbdee3d5675", "lessThan": "6c73fc931658d8cbc8a1714b326cb31eb71d16a7", "status": "affected", "versionType": "git" }, { "version": "b21d18b51b31a24d17f883b678432fbdee3d5675", "lessThan": "94cddf1e9227a171b27292509d59691819c458db", "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/pch_can.c" ], "versions": [ { "version": "2.6.37", "status": "affected" }, { "version": "0", "lessThan": "2.6.37", "status": "unaffected", "versionType": "semver" }, { "version": "4.4.295", "lessThanOrEqual": "4.4.*", "status": "unaffected", "versionType": "semver" }, { "version": "4.9.293", "lessThanOrEqual": "4.9.*", "status": "unaffected", "versionType": "semver" }, { "version": "4.14.258", "lessThanOrEqual": "4.14.*", "status": "unaffected", "versionType": "semver" }, { "version": "4.19.221", "lessThanOrEqual": "4.19.*", "status": "unaffected", "versionType": "semver" }, { "version": "5.4.165", "lessThanOrEqual": "5.4.*", "status": "unaffected", "versionType": "semver" }, { "version": "5.10.85", "lessThanOrEqual": "5.10.*", "status": "unaffected", "versionType": "semver" }, { "version": "5.15.8", "lessThanOrEqual": "5.15.*", "status": "unaffected", "versionType": "semver" }, { "version": "5.16", "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": "2.6.37", "versionEndExcluding": "4.4.295" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "2.6.37", "versionEndExcluding": "4.9.293" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "2.6.37", "versionEndExcluding": "4.14.258" 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"https://git.kernel.org/stable/c/affbad02bf80380a7403885b9fe4a1587d1bb4f3" }, { "url": "https://git.kernel.org/stable/c/3e193ef4e0a3f5bf92ede83ef214cb09d01b00aa" }, { "url": "https://git.kernel.org/stable/c/abb4eff3dcd2e583060082a18a8dbf31f02689d4" }, { "url": "https://git.kernel.org/stable/c/703dde112021c93d6e89443c070e7dbd4dea612e" }, { "url": "https://git.kernel.org/stable/c/6c73fc931658d8cbc8a1714b326cb31eb71d16a7" }, { "url": "https://git.kernel.org/stable/c/94cddf1e9227a171b27292509d59691819c458db" } ], "title": "can: pch_can: pch_can_rx_normal: fix use after free", "x_generator": { "engine": "bippy-1.2.0" } }, "adp": [ { "metrics": [ { "other": { "type": "ssvc", "content": { "timestamp": "2024-06-17T18:03:24.271974Z", "id": "CVE-2021-47520", "options": [ { "Exploitation": "none" }, { "Automatable": "no" }, { "Technical Impact": "partial" } ], "role": "CISA Coordinator", "version": "2.0.3" } } } ], "title": "CISA ADP Vulnrichment", "providerMetadata": { "orgId": 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