Multiple vulnerabilities in the sound(4) mmap path

What FreeBSD says

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).

Excerpt from the FreeBSD advisory. Read the original for the full text and the fix.