CVE-2026-80662

Quoted from the kernel CNA's own scoring file, word for word. A highlighted metric carries the most severe value CVSS v3.1 defines for it, which is what pushes the score up. source

AV:LAttack vector, local

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.

AC:LAttack complexity, low

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.

PR:LPrivileges required, low

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.

UI:NUser interaction, none

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.

S:UScope, unchanged

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.

C:HConfidentiality impact, high

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.

I:NIntegrity impact, none

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.

A:HAvailability impact, high

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.