{"dataType":"CVE_RECORD","dataVersion":"5.2","cveMetadata":{"cveId":"CVE-2021-47483","assignerOrgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","state":"PUBLISHED","assignerShortName":"Linux","dateReserved":"2024-05-22T06:20:56.200Z","datePublished":"2024-05-22T08:19:34.852Z","dateUpdated":"2026-08-05T08:48:00.568Z"},"containers":{"cna":{"providerMetadata":{"orgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","shortName":"Linux","dateUpdated":"2026-08-05T08:48:00.568Z"},"descriptions":[{"lang":"en","value":"In the Linux kernel, the following vulnerability has been resolved:\n\nregmap: Fix possible double-free in regcache_rbtree_exit()\n\nIn regcache_rbtree_insert_to_block(), when 'present' realloc failed,\nthe 'blk' which is supposed to assign to 'rbnode->block' will be freed,\nso 'rbnode->block' points a freed memory, in the error handling path of\nregcache_rbtree_init(), 'rbnode->block' will be freed again in\nregcache_rbtree_exit(), KASAN will report double-free as follows:\n\nBUG: KASAN: double-free or invalid-free in kfree+0xce/0x390\nCall Trace:\n slab_free_freelist_hook+0x10d/0x240\n kfree+0xce/0x390\n regcache_rbtree_exit+0x15d/0x1a0\n regcache_rbtree_init+0x224/0x2c0\n regcache_init+0x88d/0x1310\n __regmap_init+0x3151/0x4a80\n __devm_regmap_init+0x7d/0x100\n madera_spi_probe+0x10f/0x333 [madera_spi]\n spi_probe+0x183/0x210\n really_probe+0x285/0xc30\n\nTo fix this, moving up the assignment of rbnode->block to immediately after\nthe reallocation has succeeded so that the data structure stays valid even\nif the second reallocation fails."}],"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 regmap's local register cache (regcache_rbtree_insert_to_block), reached via driver probe/regmap init or local regmap writes through device interfaces (e.g. ASoC codecs), not by processing remote network payloads.\nAC:L - Triggering requires a GFP_KERNEL allocation failure on the second krealloc, but a local attacker can induce memory pressure to force that path; no victim state or attacker-uncontrollable race is required.\nPR:L - An unprivileged local user can drive regmap cache updates through widely deployed userspace-reachable device interfaces (notably ALSA/ASoC controls on systems with REGCACHE_RBTREE codecs) without needing root bind/module capabilities.\nUI:N - The attacker triggers the vulnerable path themselves via local operations and memory pressure; no separate victim action is required.\nS:U - Exploitation corrupts kernel heap memory within the same OS security authority (local privilege escalation), not a cross-boundary escape such as guest-to-host or IOMMU bypass.\nC:H - The dangling rbnode->block after the failed realloc is a use-after-free/double-free primitive, which can be heap-groomed to obtain arbitrary kernel memory disclosure.\nI:H - Double-free/UAF on the cache block enables heap corruption suitable for arbitrary write and control-flow hijacking in the kernel.\nA:H - The double-free in regcache_rbtree_exit() (and UAF on later cache access) reliably causes kernel oops/panic or otherwise crashes the system."}]}],"affected":[{"product":"Linux","vendor":"Linux","defaultStatus":"unaffected","repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["drivers/base/regmap/regcache-rbtree.c"],"versions":[{"version":"3f4ff561bc88b074d5e868dde4012d89cbb06c87","lessThan":"e72dce9afbdbfa70d9b44f5908a50ff6c4858999","status":"affected","versionType":"git"},{"version":"3f4ff561bc88b074d5e868dde4012d89cbb06c87","lessThan":"fc081477b47dfc3a6cb50a96087fc29674013fc2","status":"affected","versionType":"git"},{"version":"3f4ff561bc88b074d5e868dde4012d89cbb06c87","lessThan":"758ced2c3878ff789801e6fee808e185c5cf08d6","status":"affected","versionType":"git"},{"version":"3f4ff561bc88b074d5e868dde4012d89cbb06c87","lessThan":"3dae1a4eced3ee733d7222e69b8a55caf2d61091","status":"affected","versionType":"git"},{"version":"3f4ff561bc88b074d5e868dde4012d89cbb06c87","lessThan":"1cead23c1c0bc766dacb900a3b0269f651ad596f","status":"affected","versionType":"git"},{"version":"3f4ff561bc88b074d5e868dde4012d89cbb06c87","lessThan":"36e911a16b377bde0ad91a8c679069d0d310b1a6","status":"affected","versionType":"git"},{"version":"3f4ff561bc88b074d5e868dde4012d89cbb06c87","lessThan":"50cc1462a668dc62949a1127388bc3af785ce047","status":"affected","versionType":"git"},{"version":"3f4ff561bc88b074d5e868dde4012d89cbb06c87","lessThan":"55e6d8037805b3400096d621091dfbf713f97e83","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/base/regmap/regcache-rbtree.c"],"versions":[{"version":"3.12","status":"affected"},{"version":"0","lessThan":"3.12","status":"unaffected","versionType":"semver"},{"version":"4.4.291","lessThanOrEqual":"4.4.*","status":"unaffected","versionType":"semver"},{"version":"4.9.289","lessThanOrEqual":"4.9.*","status":"unaffected","versionType":"semver"},{"version":"4.14.254","lessThanOrEqual":"4.14.*","status":"unaffected","versionType":"semver"},{"version":"4.19.215","lessThanOrEqual":"4.19.*","status":"unaffected","versionType":"semver"},{"version":"5.4.157","lessThanOrEqual":"5.4.*","status":"unaffected","versionType":"semver"},{"version":"5.10.77","lessThanOrEqual":"5.10.*","status":"unaffected","versionType":"semver"},{"version":"5.14.16","lessThanOrEqual":"5.14.*","status":"unaffected","versionType":"semver"},{"version":"5.15","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":"3.12","versionEndExcluding":"4.4.291"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"3.12","versionEndExcluding":"4.9.289"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"3.12","versionEndExcluding":"4.14.254"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"3.12","versionEndExcluding":"4.19.215"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"3.12","versionEndExcluding":"5.4.157"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"3.12","versionEndExcluding":"5.10.77"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"3.12","versionEndExcluding":"5.14.16"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"3.12","versionEndExcluding":"5.15"}]}]}],"references":[{"url":"https://git.kernel.org/stable/c/e72dce9afbdbfa70d9b44f5908a50ff6c4858999"},{"url":"https://git.kernel.org/stable/c/fc081477b47dfc3a6cb50a96087fc29674013fc2"},{"url":"https://git.kernel.org/stable/c/758ced2c3878ff789801e6fee808e185c5cf08d6"},{"url":"https://git.kernel.org/stable/c/3dae1a4eced3ee733d7222e69b8a55caf2d61091"},{"url":"https://git.kernel.org/stable/c/1cead23c1c0bc766dacb900a3b0269f651ad596f"},{"url":"https://git.kernel.org/stable/c/36e911a16b377bde0ad91a8c679069d0d310b1a6"},{"url":"https://git.kernel.org/stable/c/50cc1462a668dc62949a1127388bc3af785ce047"},{"url":"https://git.kernel.org/stable/c/55e6d8037805b3400096d621091dfbf713f97e83"}],"title":"regmap: 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