{ "dataType": "CVE_RECORD", "dataVersion": "5.2", "cveMetadata": { "cveId": "CVE-2021-47282", "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "state": "PUBLISHED", "assignerShortName": "Linux", "dateReserved": "2024-05-21T13:27:52.128Z", "datePublished": "2024-05-21T14:20:08.155Z", "dateUpdated": "2026-08-05T08:47:04.965Z" }, "containers": { "cna": { "providerMetadata": { "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "shortName": "Linux", "dateUpdated": "2026-08-05T08:47:04.965Z" }, "descriptions": [ { "lang": "en", "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nspi: bcm2835: Fix out-of-bounds access with more than 4 slaves\n\nCommit 571e31fa60b3 (\"spi: bcm2835: Cache CS register value for\n->prepare_message()\") limited the number of slaves to 3 at compile-time.\nThe limitation was necessitated by a statically-sized array prepare_cs[]\nin the driver private data which contains a per-slave register value.\n\nThe commit sought to enforce the limitation at run-time by setting the\ncontroller's num_chipselect to 3: Slaves with a higher chipselect are\nrejected by spi_add_device().\n\nHowever the commit neglected that num_chipselect only limits the number\nof *native* chipselects. If GPIO chipselects are specified in the\ndevice tree for more than 3 slaves, num_chipselect is silently raised by\nof_spi_get_gpio_numbers() and the result are out-of-bounds accesses to\nthe statically-sized array prepare_cs[].\n\nAs a bandaid fix which is backportable to stable, raise the number of\nallowed slaves to 24 (which \"ought to be enough for anybody\"), enforce\nthe limitation on slave ->setup and revert num_chipselect to 3 (which is\nthe number of native chipselects supported by the controller).\nAn upcoming for-next commit will allow an arbitrary number of slaves." } ], "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 bcm2835 SPI host driver is reached through local device registration and SPI transfers (e.g. spidev or bound slave drivers) after the controller is instantiated from the platform/device tree; it is not reachable via network protocols or by merely attaching a hot-plugged peripheral.\nAC:L - Once more than four GPIO chipselects are present in the device tree, of_spi_get_gpio_numbers() raises num_chipselect and spi_add_device() accepts high CS indices, so bcm2835_spi_setup()/prepare_message()/DMA paths reliably perform the out-of-bounds accesses with no race or other attacker-uncontrollable condition.\nPR:L - On affected Raspberry Pi and industrial bcm2835 systems, unprivileged local users can open SPI device nodes and trigger transfers that exercise the OOB paths; DT configuration establishing the vulnerable CS count is a realistic deployment precondition rather than a requirement for high privileges at exploit time.\nUI:N - No separate victim action is required; registration at probe and subsequent SPI I/O invoke the vulnerable code without interactive user cooperation.\nS:U - The corruption is confined to kernel memory in the same SPI controller privilege domain and does not cross a VM, IOMMU, or other security authority boundary.\nC:H - Out-of-bounds reads of prepare_cs[] and adjacent bcm2835_spi fields, plus heap corruption from clear_rx_cs[] writes past the allocation, are memory-corruption primitives that can be leveraged for information disclosure.\nI:H - Out-of-bounds writes into prepare_cs[] (overwriting later struct fields such as pointers) and past clear_rx_cs[] into the heap, together with submission of invalid clear_rx_desc[] DMA descriptors, enable integrity compromise and control-flow/DMA abuse.\nA:H - Invalid pointer and DMA descriptor use from the corrupted bcm2835_spi state can cause kernel oops/panic or hangs, yielding a full availability impact." } ] } ], "affected": [ { "product": "Linux", "vendor": "Linux", "defaultStatus": "unaffected", "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "programFiles": [ "drivers/spi/spi-bcm2835.c" ], "versions": [ { "version": "571e31fa60b3697d5db26140e16d5c45c51c9815", "lessThan": "b5502580cf958b094f3b69dfe4eece90eae01fbc", "status": "affected", "versionType": "git" }, { "version": "571e31fa60b3697d5db26140e16d5c45c51c9815", "lessThan": "82a8ffba54d31e97582051cb56ba1f988018681e", "status": "affected", "versionType": "git" }, { "version": "571e31fa60b3697d5db26140e16d5c45c51c9815", "lessThan": "01415ff85a24308059e06ca3e97fd7bf75648690", "status": "affected", "versionType": "git" }, { "version": "571e31fa60b3697d5db26140e16d5c45c51c9815", "lessThan": "13817d466eb8713a1ffd254f537402f091d48444", "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/spi/spi-bcm2835.c" ], "versions": [ { "version": "5.4", "status": "affected" }, { "version": "0", "lessThan": "5.4", "status": "unaffected", "versionType": "semver" }, { "version": "5.4.126", "lessThanOrEqual": "5.4.*", "status": "unaffected", "versionType": "semver" }, { "version": "5.10.44", "lessThanOrEqual": "5.10.*", "status": "unaffected", "versionType": "semver" }, { "version": "5.12.11", "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": "5.4.126" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "5.4", "versionEndExcluding": "5.10.44" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "5.4", "versionEndExcluding": "5.12.11" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "5.4", "versionEndExcluding": "5.13" } ] } ] } ], "references": [ { "url": "https://git.kernel.org/stable/c/b5502580cf958b094f3b69dfe4eece90eae01fbc" }, { "url": "https://git.kernel.org/stable/c/82a8ffba54d31e97582051cb56ba1f988018681e" }, { "url": "https://git.kernel.org/stable/c/01415ff85a24308059e06ca3e97fd7bf75648690" }, { "url": "https://git.kernel.org/stable/c/13817d466eb8713a1ffd254f537402f091d48444" } ], "title": "spi: bcm2835: Fix out-of-bounds access with more than 4 slaves", "x_generator": { "engine": "bippy-1.2.0" } }, "adp": [ { "title": "CISA ADP Vulnrichment", "metrics": [ { "other": { "type": "ssvc", "content": { "id": "CVE-2021-47282", "role": "CISA Coordinator", "options": [ { "Exploitation": "none" }, { "Automatable": "no" }, { "Technical Impact": "partial" } ], "version": "2.0.3", "timestamp": "2024-05-23T17:10:17.644618Z" } } } ], "providerMetadata": { "orgId": "134c704f-9b21-4f2e-91b3-4a467353bcc0", "shortName": "CISA-ADP", "dateUpdated": "2024-06-04T17:14:52.641Z" } }, { "providerMetadata": { "orgId": "af854a3a-2127-422b-91ae-364da2661108", "shortName": "CVE", "dateUpdated": "2024-08-04T05:32:08.008Z" }, "title": "CVE Program Container", "references": [ { "url": "https://git.kernel.org/stable/c/b5502580cf958b094f3b69dfe4eece90eae01fbc", "tags": [ "x_transferred" ] }, { "url": "https://git.kernel.org/stable/c/82a8ffba54d31e97582051cb56ba1f988018681e", "tags": [ "x_transferred" ] }, { "url": "https://git.kernel.org/stable/c/01415ff85a24308059e06ca3e97fd7bf75648690", "tags": [ "x_transferred" ] }, { "url": "https://git.kernel.org/stable/c/13817d466eb8713a1ffd254f537402f091d48444", "tags": [ "x_transferred" ] } ] } ] } }