Problem Description:
The sound(4) driver contained two memory-safety errors in its
mmap(2) support.
First, dsp_mmap_single() validated the requested mapping by checking
the sum of the user-supplied offset and length against the buffer
size. This addition could overflow, so that a large offset and
length wrapped around and passed the check. The offset was then
narrowed from 64 to 32 bits when converted to a buffer address,
yielding a mapping that extended past the audio buffer into unrelated
kernel memory. (CVE-2026-45258)
Second, the audio buffer backing a mapping could be freed when the
device was closed even though the mapping remained valid. The freed
memory could then be reused elsewhere while still accessible through
the stale mapping. (CVE-2026-49417)
Impact:
The /dev/dsp device nodes are world-accessible by default. On
a system with an audio device, either issue allows an unprivileged
local user to read and write kernel memory, which can be used to
escalate privileges, potentially gaining full control of the affected
system. At a minimum, an attacker can crash the kernel, resulting
in a Denial of Service (DoS).