{"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"]}]}]}}