CVE-2026-45994

Summary

In the Linux kernel, the following vulnerability has been resolved:

ibmasm: fix OOB reads in command_file_write due to missing size checks

The command_file_write() handler allocates a kernel buffer of exactly count bytes and copies user data into it, but does not validate the buffer against the dot command protocol before passing it to get_dot_command_size() and get_dot_command_timeout().

Since both the allocation size (count) and the header fields (command_size, data_size) are independently user-controlled, an attacker can cause get_dot_command_size() to return a value exceeding the allocation, triggering OOB reads in get_dot_command_timeout() and an out-of-bounds memcpy_toio() that leaks kernel heap memory to the service processor.

Fix with two guards: reject writes smaller than sizeof(struct dot_command_header) before allocation, then after copying user data reject commands where the buffer is smaller than the total size declared by the header (sizeof(header) + command_size + data_size). This ensures all subsequent header and payload field accesses stay within the buffer.

Affected Software

Weaknesses

References

• https://git.kernel.org/stable/c/44ee19422aa82a6847594866de7e5a31e4ef98b3
• https://git.kernel.org/stable/c/7b8a574da5d7ea99b943f7a3458a17a1d95e8838
• https://git.kernel.org/stable/c/d50e2019c9d7c433f56d9dff65703eb904aa1fb1
• https://git.kernel.org/stable/c/a672682d39dd34e2b5ba4feb436723bed65125ff
• https://git.kernel.org/stable/c/aefc1a97da17d8309974690c8a03e439a91ebb1c
• https://git.kernel.org/stable/c/ee5737891464030a189837467df3b81a273718ad
• https://git.kernel.org/stable/c/d0fb4d1dc43f8d5179917a2daaa82680993d4cdf
• https://git.kernel.org/stable/c/0eb09f737428e482a32a2e31e5e223f2b35a71d3

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