CVE intelligence and bounded remediation

CVE-2026-46064 — Linux Linux Kernel security vulnerability

In the Linux kernel, the following vulnerability has been resolved: ibmasm: fix heap over-read in ibmasm_send_i2o_message() The ibmasm_send_i2o_message() function uses get_dot_command_size() to compute the byte count for memcpy_toio(), but this value is derived from user-controlled fields in the dot_command_header (command_size: u8, data_size: u16) and is never validated against the actual allocation size. A root user can write a small buffer with inflated header fields, causing memcpy_toio() to read up to ~65 KB past the end of the allocation into adjacent kernel heap, which is then forwarded to the service processor over MMIO. Silently clamping the copy size is not sufficient: if the header fields claim a larger size than the buffer, the SP receives a dot command whose own header is inconsistent with the I2O message length, which can cause the SP to desynchronize. Reject such commands outright by returning failure. Validate command_size before calling get_mfa_inbound() to avoid leaking an I2O message frame: reading INBOUND_QUEUE_PORT dequeues a hardware frame from the controller's free pool, and returning without a corresponding set_mfa_inbound() call would permanently exhaust i…

Severity

High

CVSS

7.1 (3.1)

Published

2026-05-27

CISA KEV

Not currently listed

Ecosystem

linux/kernel

Weaknesses

CWE-125