Bug 2482038 (CVE-2026-45994) - CVE-2026-45994 kernel: ibmasm: fix OOB reads in command_file_write due to missing size checks
Summary: CVE-2026-45994 kernel: ibmasm: fix OOB reads in command_file_write due to mis...
Keywords:
Status: NEW
Alias: CVE-2026-45994
Product: Security Response
Classification: Other
Component: vulnerability
Version: unspecified
Hardware: All
OS: Linux
medium
medium
Target Milestone: ---
Assignee: Product Security
QA Contact:
URL:
Whiteboard:
Depends On:
Blocks:
TreeView+ depends on / blocked
 
Reported: 2026-05-27 15:08 UTC by OSIDB Bzimport
Modified: 2026-05-27 21:42 UTC (History)
2 users (show)

Fixed In Version:
Clone Of:
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Description OSIDB Bzimport 2026-05-27 15:08:16 UTC
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.


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