205 lines
12 KiB
JSON
205 lines
12 KiB
JSON
{
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"dataType": "CVE_RECORD",
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"dataVersion": "5.2",
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"cveMetadata": {
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"cveId": "CVE-2026-80662",
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"assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
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"state": "PUBLISHED",
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"assignerShortName": "Linux",
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"dateReserved": "2026-08-26T14:34:25.781Z",
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"datePublished": "2026-08-28T06:49:06.277Z",
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"dateUpdated": "2026-10-21T12:46:49.254Z"
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},
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"containers": {
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"cna": {
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"providerMetadata": {
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"orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
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"shortName": "Linux",
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"dateUpdated": "2026-10-21T12:46:49.254Z"
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},
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"descriptions": [
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{
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"lang": "en",
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"value": "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 ]"
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}
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],
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"metrics": [
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{
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"cvssV3_1": {
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"version": "3.1",
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"vectorString": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:H",
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"baseScore": 7.1,
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"baseSeverity": "HIGH"
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},
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"scenarios": [
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{
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"lang": "en",
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"value": "AV:L - The bug is only reached in kernel CXL RAS error handling (cxl_handle_ras via PCI AER cxl_error_detected, and CPER paths cxl_cper_post_prot_err/extlog_cxl_cper_handle_prot_err). Disclosure requires reading tracefs; there is no network, adjacent-radio, or direct physical-bus syscall entry to the vulnerable memcpy/readl sites.\nAC:L - With CAP_SYS_ADMIN, ACPI/CXL EINJ via debugfs einj_inject deterministically injects uncorrectable CXL protocol errors that traverse cxl_cper_handle_prot_err/cxl_handle_ras. Without root, a tracing-group member on CXL servers running rasdaemon can reliably capture the leak whenever organic uncorrectable RAS events occur.\nPR:L - Exploitation requires reading cxl_aer_uncorrectable_error data from tracefs (TRACE_MODE_READ 0440), routinely granted to tracing-group/rasdaemon service accounts on CXL/RAS deployments. Triggering on demand uses debugfs EINJ (root) or natural hardware errors; no init-namespace-only capability beyond tracefs DAC is needed for the stack leak.\nUI:N - Once CXL tracepoints are enabled (as rasdaemon does automatically), uncorrectable RAS/CPER processing copies the overlong header_log during kernel error handling. No victim mount, login, or interactive action is required beyond the attacker (or environment) having tracefs access when an error fires.\nS:U - The flaw leaks kernel stack/MMIO data into the trace ring buffer within the host kernel. Impact stays in the same OS security authority (local privilege/information gain) and does not cross guest/host, IOMMU, or container hardware trust boundaries.\nC:H - TP_fast_assign memcpy() copies 512 bytes from a 64-byte ras_cap.header_log on the stack, leaking 448 bytes of kernel stack into tracefs. header_log_copy() also readl()s 128 dwords from an 88-byte RAS iomap, an out-of-bounds read of adjacent MMIO/device memory.\nI:N - Both failure modes are out-of-bounds reads only (stack and MMIO). The trace event stores leaked bytes in the ring buffer but does not corrupt attacker-controlled memory or provide a direct arbitrary-write primitive.\nA:H - header_log_copy() performs 448 bytes of MMIO reads past the devm_ioremap() RAS window (0x58 bytes), which can provoke CPU/MMU faults or platform errors on out-of-range readl(). Uncorrectable-error handling itself can disable CXL.mem devices and force resets, impacting availability."
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}
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]
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}
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],
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"affected": [
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{
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"product": "Linux",
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"vendor": "Linux",
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"defaultStatus": "unaffected",
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"repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
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"programFiles": [
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"drivers/cxl/core/ras.c",
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"drivers/cxl/core/trace.h",
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"drivers/cxl/cxl.h"
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],
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"versions": [
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{
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"version": "2905cb5236cba63a5dc8a83752dcc31f3cc819f9",
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"lessThan": "d031617045dc743764ea574432e5c2a3757b4e57",
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"status": "affected",
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"versionType": "git"
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},
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{
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"version": "2905cb5236cba63a5dc8a83752dcc31f3cc819f9",
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"lessThan": "e3e8f3b760bcf6a4b3aec412015b74b578729006",
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"status": "affected",
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"versionType": "git"
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},
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{
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"version": "2905cb5236cba63a5dc8a83752dcc31f3cc819f9",
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"lessThan": "6fc1919a6f2ed541484dd1f6cd93374044f8fd3d",
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"status": "affected",
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"versionType": "git"
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},
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{
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"version": "2905cb5236cba63a5dc8a83752dcc31f3cc819f9",
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"lessThan": "fc5eb0962a5e50d64e711817cc24d67df2d90528",
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"status": "affected",
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"version": "2905cb5236cba63a5dc8a83752dcc31f3cc819f9",
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"lessThan": "c268f949e219f9e179558e836f457f6c5fbec416",
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"status": "affected",
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}
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]
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},
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{
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"product": "Linux",
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"vendor": "Linux",
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"defaultStatus": "affected",
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"repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
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"programFiles": [
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"drivers/cxl/core/ras.c",
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"drivers/cxl/core/trace.h",
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"drivers/cxl/cxl.h"
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],
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"versions": [
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{
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"version": "6.2",
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"status": "affected"
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},
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{
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"version": "0",
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"lessThan": "6.2",
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"status": "unaffected",
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"versionType": "semver"
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},
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{
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"version": "6.6.160",
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"lessThanOrEqual": "6.6.*",
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"status": "unaffected",
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"versionType": "semver"
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},
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{
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"version": "6.12.114",
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"lessThanOrEqual": "6.12.*",
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"status": "unaffected",
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"versionType": "semver"
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},
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{
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"version": "6.18.42",
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"lessThanOrEqual": "6.18.*",
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"status": "unaffected",
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"versionType": "semver"
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},
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{
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"version": "7.1.5",
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"lessThanOrEqual": "7.1.*",
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"status": "unaffected",
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"versionType": "semver"
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},
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{
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"version": "7.2",
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"lessThanOrEqual": "*",
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"status": "unaffected",
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"versionType": "original_commit_for_fix"
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}
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]
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}
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],
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"cpeApplicability": [
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"negate": false,
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"references": [
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"url": "https://git.kernel.org/stable/c/d031617045dc743764ea574432e5c2a3757b4e57"
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},
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{
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"url": "https://git.kernel.org/stable/c/e3e8f3b760bcf6a4b3aec412015b74b578729006"
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},
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{
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"url": "https://git.kernel.org/stable/c/6fc1919a6f2ed541484dd1f6cd93374044f8fd3d"
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{
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"url": "https://git.kernel.org/stable/c/fc5eb0962a5e50d64e711817cc24d67df2d90528"
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{
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"url": "https://git.kernel.org/stable/c/c268f949e219f9e179558e836f457f6c5fbec416"
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}
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],
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"title": "cxl: Fix CXL_HEADERLOG_SIZE to match RAS Capability size",
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