{"id":"CVE-2026-80662","aliases":[],"url":"https://o3.security/vulnerability/CVE-2026-80662","summary":"cxl: Fix CXL_HEADERLOG_SIZE to match RAS Capability size","details":"In the Linux kernel, the following vulnerability has been resolved:\n\ncxl: Fix CXL_HEADERLOG_SIZE to match RAS Capability size\n\nThe CXL r4.0 8.2.4.17.7 RAS Capability Structure has total length 0x58\nbytes (CXL_RAS_CAPABILITY_LENGTH); the Header Log occupies the trailing\n64 bytes at offset 0x18.  CXL_HEADERLOG_SIZE was defined as SZ_512,\neight times the actual on-device size.\n\nheader_log_copy() reads CXL_HEADERLOG_SIZE_U32 (128) dwords from the\nRAS capability iomap, overrunning the 88-byte mapping by 448 bytes.\nThe cxl_aer_uncorrectable_error trace event memcpy()s CXL_HEADERLOG_SIZE\n(512) bytes from its source.  For the CPER caller the source is\nstruct cxl_ras_capability_regs::header_log[16] (64 bytes) embedded in a\nstack-local cxl_cper_prot_err_work_data, so the memcpy reads 448 bytes\nof kernel stack into the trace event ring buffer where userspace can\nread it via tracefs.\n\nSet CXL_HEADERLOG_SIZE to 64 and derive CXL_HEADERLOG_SIZE_U32 from it,\nbringing all iomap readers into agreement on 16 dwords.  Userspace tools\nsuch as rasdaemon have grown a dependency on the buggy 512-byte (128 u32)\nheader_log layout in the cxl_aer_uncorrectable_error trace event.  Add\nCXL_HEADERLOG_TRACE_SIZE_U32 = 128 and use it for the trace event\n__array and its memcpy to preserve that ABI.  Both callers now pass a\nzero-filled u32[CXL_HEADERLOG_TRACE_SIZE_U32] staging buffer with only\nthe first CXL_HEADERLOG_SIZE_U32 (16) entries populated from hardware;\nthe remaining 112 u32s are zero-padded, keeping the 512-byte trace ring\nbuffer layout intact.\n\n[ dj: Replaced 64 with SZ_64 per RichardC ]","published":"2026-08-28T06:49:06.277Z","modified":"2026-08-30T03:47:21.701437549Z","cvss":{"score":7.1,"severity":"HIGH","vector":"CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:H"},"epss":null,"cisaKev":null,"exploitsKnown":null,"affectedPackages":[{"ecosystem":"Linux","name":"Kernel","fixedVersion":"6.18.42"}],"fix":null,"references":[{"type":"WEB","url":"https://git.kernel.org/stable/c/6fc1919a6f2ed541484dd1f6cd93374044f8fd3d"},{"type":"WEB","url":"https://git.kernel.org/stable/c/c268f949e219f9e179558e836f457f6c5fbec416"},{"type":"WEB","url":"https://git.kernel.org/stable/c/fc5eb0962a5e50d64e711817cc24d67df2d90528"},{"type":"ADVISORY","url":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/80xxx/CVE-2026-80662.json"},{"type":"ADVISORY","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-80662"},{"type":"PACKAGE","url":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git"}],"provenance":{"sources":["OSV.dev","FIRST.org (EPSS)"],"lastVerified":"2026-08-30T03:47:21.701437549Z"}}