{"id":"CVE-2023-53487","title":"powerpc/rtas_flash: allow user copy to flash block cache objects","summary":"In the Linux kernel, the following vulnerability has been resolved:\n\npowerpc/rtas_flash: allow user copy to flash block cache objects\n\nWith hardened usercopy enabled (CONFIG_HARDENED_USERCOPY=y), using the\n/proc/powerpc/rtas/firmware_upd…","severity":"none","vendor":"Linux","product":"Linux","affected":["Linux >= 6d07d1cd300f4c7e16005f881fea388164999cc8 < 8f09cc15dcd91d16562400c51d24c7be0d5796fa","Linux >= 6d07d1cd300f4c7e16005f881fea388164999cc8 < 1d29e21ed09fa668416fa7721e08d451b9903485","Linux >= 6d07d1cd300f4c7e16005f881fea388164999cc8 < 0ba7f969be599e21d4b1f1e947593de6515f4996","Linux >= 6d07d1cd300f4c7e16005f881fea388164999cc8 < 8ef25fb13494e35c6dbe15445c7875fa92bc3e8b","Linux >= 6d07d1cd300f4c7e16005f881fea388164999cc8 < b8fee83aa4ed3846c7f50a0b364bc699f48d96e5","Linux >= 6d07d1cd300f4c7e16005f881fea388164999cc8 < 6acb8a453388374fafb3c3b37534b675b2aa0ae1","Linux >= 6d07d1cd300f4c7e16005f881fea388164999cc8 < 4f3175979e62de3b929bfa54a0db4b87d36257a7","Linux 4.16"],"ssvc":{"exploitation":"none","automatable":"no","technicalImpact":"partial","timestamp":"2026-11-05T20:22:14.298181Z"},"published":"2025-10-01","updated":"2026-11-05","sourceUpdated":"2026-11-05T20:31:11.542Z","source":"CVEORG","sourceUrl":"https://www.cve.org/CVERecord?id=CVE-2023-53487","references":[{"url":"https://git.kernel.org/stable/c/8f09cc15dcd91d16562400c51d24c7be0d5796fa"},{"url":"https://git.kernel.org/stable/c/1d29e21ed09fa668416fa7721e08d451b9903485"},{"url":"https://git.kernel.org/stable/c/0ba7f969be599e21d4b1f1e947593de6515f4996"},{"url":"https://git.kernel.org/stable/c/8ef25fb13494e35c6dbe15445c7875fa92bc3e8b"},{"url":"https://git.kernel.org/stable/c/b8fee83aa4ed3846c7f50a0b364bc699f48d96e5"},{"url":"https://git.kernel.org/stable/c/6acb8a453388374fafb3c3b37534b675b2aa0ae1"},{"url":"https://git.kernel.org/stable/c/4f3175979e62de3b929bfa54a0db4b87d36257a7"}],"tags":["cve.org"],"epss":0.00168,"epssPercentile":0.06189,"ingestedAt":"2026-11-05T22:38:31.802Z","slug":"CVE-2023-53487","body":"## Overview\n\nIn the Linux kernel, the following vulnerability has been resolved:\n\npowerpc/rtas_flash: allow user copy to flash block cache objects\n\nWith hardened usercopy enabled (CONFIG_HARDENED_USERCOPY=y), using the\n/proc/powerpc/rtas/firmware_update interface to prepare a system\nfirmware update yields a BUG():\n\n  kernel BUG at mm/usercopy.c:102!\n  Oops: Exception in kernel mode, sig: 5 [#1]\n  LE PAGE_SIZE=64K MMU=Hash SMP NR_CPUS=2048 NUMA pSeries\n  Modules linked in:\n  CPU: 0 PID: 2232 Comm: dd Not tainted 6.5.0-rc3+ #2\n  Hardware name: IBM,8408-E8E POWER8E (raw) 0x4b0201 0xf000004 of:IBM,FW860.50 (SV860_146) hv:phyp pSeries\n  NIP:  c0000000005991d0 LR: c0000000005991cc CTR: 0000000000000000\n  REGS: c0000000148c76a0 TRAP: 0700   Not tainted  (6.5.0-rc3+)\n  MSR:  8000000000029033 <SF,EE,ME,IR,DR,RI,LE>  CR: 24002242  XER: 0000000c\n  CFAR: c0000000001fbd34 IRQMASK: 0\n  [ ... GPRs omitted ... ]\n  NIP usercopy_abort+0xa0/0xb0\n  LR  usercopy_abort+0x9c/0xb0\n  Call Trace:\n    usercopy_abort+0x9c/0xb0 (unreliable)\n    __check_heap_object+0x1b4/0x1d0\n    __check_object_size+0x2d0/0x380\n    rtas_flash_write+0xe4/0x250\n    proc_reg_write+0xfc/0x160\n    vfs_write+0xfc/0x4e0\n    ksys_write+0x90/0x160\n    system_call_exception+0x178/0x320\n    system_call_common+0x160/0x2c4\n\nThe blocks of the firmware image are copied directly from user memory\nto objects allocated from flash_block_cache, so flash_block_cache must\nbe created using kmem_cache_create_usercopy() to mark it safe for user\naccess.\n\n[mpe: Trim and indent oops]\n\n## Affected\n\n- `Linux >= 6d07d1cd300f4c7e16005f881fea388164999cc8 < 8f09cc15dcd91d16562400c51d24c7be0d5796fa`\n- `Linux >= 6d07d1cd300f4c7e16005f881fea388164999cc8 < 1d29e21ed09fa668416fa7721e08d451b9903485`\n- `Linux >= 6d07d1cd300f4c7e16005f881fea388164999cc8 < 0ba7f969be599e21d4b1f1e947593de6515f4996`\n- `Linux >= 6d07d1cd300f4c7e16005f881fea388164999cc8 < 8ef25fb13494e35c6dbe15445c7875fa92bc3e8b`\n- `Linux >= 6d07d1cd300f4c7e16005f881fea388164999cc8 < b8fee83aa4ed3846c7f50a0b364bc699f48d96e5`\n- `Linux >= 6d07d1cd300f4c7e16005f881fea388164999cc8 < 6acb8a453388374fafb3c3b37534b675b2aa0ae1`\n- `Linux >= 6d07d1cd300f4c7e16005f881fea388164999cc8 < 4f3175979e62de3b929bfa54a0db4b87d36257a7`\n- `Linux 4.16`\n\n## Remediation\n\nRefer to the linked advisories for vendor-supplied fixes and affected version ranges.","depth":"sunlit","depthScore":3,"depthScoreParts":{"impact":2.8,"likelihood":0,"exploitation":0,"ransomware":0},"changes":[]}