CVE-2026-89489

Published: September 15, 2026Last modified: September 15, 2026

Description

In the Linux kernel, the following vulnerability has been resolved: openrisc: fix arbitrary kernel memory access via or1k_atomic syscall sys_or1k_atomic() (syscall 244 in the "or1k" ABI) takes two user pointers, v1 and v2, and swaps the words they point to in hand-written assembly. l.lwz r29,0(r4) l.lwz r27,0(r5) l.sw 0(r4),r27 l.sw 0(r5),r29 The pointers are not checked with access_ok(). The four memory accesses also have no exception table entries. A caller passes a kernel address as either pointer, and the syscall reads from and writes to it directly. This gives an unprivileged process a kernel read/write primitive. It overwrites kernel data such as the sys_call_table, gaining code execution in kernel context. Check both pointers before entering the critical section. Add fixups for the four memory accesses so faults on valid but unmapped user addresses return -EFAULT. [[email protected]: fix comment style]

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References

• https://git.kernel.org/stable/c/78004e9a87f240df03e2f73120d291763c32e0a7
• https://git.kernel.org/stable/c/a520e8cac54fb403f3800125b606f55fcad42cb9
• https://git.kernel.org/stable/c/b53435c079c78f89f70a62dd5a322cca4e292b34
• https://git.kernel.org/stable/c/d64a75369cd0f2ee79afcc9d9ca34a3890989379