CVE-2026-46064
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…
Does this matter?
High impact if exploited, but EPSS currently rates exploitation as unlikely (0.14%). Schedule it in the normal patch cycle and watch for a rise in EPSS or a public exploit.
Description
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 it. Additionally, clamp command_size to I2O_COMMAND_SIZE before the memcpy_toio() so the MMIO write stays within the I2O message frame, consistent with the clamping already performed by outgoing_message_size() for the header field.
- CVSS 3.1
- 7.1 HIGHCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:H
- EPSS
- 0.14% probability · 4th percentile
- CISA KEV
- Not listed
- Weakness
- CWE-125
- Affected
- linux/linux kernel
- Source
- 416baaa9-dc9f-4396-8d5f-8c081fb06d67
References
- https://git.kernel.org/stable/c/9aad71144fa3682cca3837a06c8623016790e7ecPatch
- https://git.kernel.org/stable/c/9e8f6c9d4ecddda2f28baa1678340286cff3969cPatch
- https://git.kernel.org/stable/c/b870f652877bfbe321bd0f4096fc37a93296f7b6Patch
- https://git.kernel.org/stable/c/c1c2417c60dbdca5ebb00462f21ee71c2d7f7083Patch
- https://git.kernel.org/stable/c/ca1c857e2bb74a9fc0606128334f85316d57067bPatch
- https://git.kernel.org/stable/c/ce57fa439bd1b5d664f334a0c3e3f0e42abb0153Patch
- https://git.kernel.org/stable/c/fd19eb1c75047a4ed4e855f56cafd704dc3914e0Patch
- https://git.kernel.org/stable/c/fe31722b0194ff76bf8b461e8bf97a2081147787Patch
Source: NVD record, EPSS from FIRST.org, KEV from CISA. Refreshed daily.