CVE-2026-46179: Linux Kernel ASoC SOF Divide-by-Zero Denial-of-Service Vulnerability

Technical summary

CVE-2026-46179 is a divide-by-zero flaw in the Linux kernel's SOF (Sound Open Firmware) driver pointer reporting mechanism. When the kernel calculates the I/O frame position for a compressed stream, it divides the current position by (number of channels × container bytes). Since these parameters default to zero and are only set during stream parameter configuration, an unconfigured stream can cause division by zero. The vulnerability occurs because the kernel does not validate that these values are non-zero before performing the calculation. An attacker with local access to audio resources can exploit this to crash the audio subsystem or the entire kernel, depending on kernel configuration and crash handling policies.

Business impact

Organizations running vulnerable Linux kernels with audio subsystems exposed to untrusted local users face availability risk. Desktop environments, audio workstations, containerized deployments, and systems offering local audio access to multiple users are most exposed. A malicious or compromised local process can reliably trigger a kernel panic or audio subsystem hang, disrupting services and requiring manual recovery. While this is not a privilege escalation or confidentiality breach, denial-of-service availability attacks can impact business continuity, especially for audio-dependent workflows or always-on services.

Affected systems

The Linux kernel is affected across all versions prior to the fix. The vulnerability is present in ASoC SOF driver code and impacts any system with this driver enabled and compiled into the kernel or loaded as a module. Typical exposure includes: Linux desktops and laptops with audio capabilities, audio workstations, containerized environments with audio passthrough, IoT devices with audio functionality, and embedded Linux systems using SOF. Server deployments without active audio subsystem usage are lower risk but remain vulnerable if the code path is reachable.

Exploitability

Exploitation requires local system access and permissions to interact with the audio subsystem. The attack is straightforward: trigger audio stream pointer operations on a stream that has not been properly configured with channel and container byte parameters. No special privileges, network access, or complex exploitation techniques are required beyond basic audio API usage. Any local user with audio access can execute this attack, making it highly exploitable in multi-user or container-based environments. The CVSS vector (AV:L/AC:L/PR:L/UI:N/S:U) reflects these characteristics: local attack vector, low attack complexity, low privilege requirement.

Remediation

Apply a kernel update that includes validation of stream parameters before performing pointer calculations. The fix adds a check to ensure that the number of channels and container bytes are non-zero, returning an error if either is zero rather than proceeding to divide-by-zero. Verify the fix against your vendor's kernel advisory to confirm the exact patch version required. Interim mitigation includes restricting audio subsystem access to trusted users only, though this does not eliminate the underlying vulnerability.

Patch guidance

Monitor your Linux distribution's kernel updates for patches addressing CVE-2026-46179. Apply kernel updates through your standard change management process. For distributions with extended support (RHEL, Ubuntu LTS, Debian stable), patches typically arrive within weeks of the public disclosure. Test patches in a non-production environment first, as kernel updates require reboot. If you maintain a custom kernel build, backport the fix from the upstream Linux kernel repository or apply vendor patches. Verify patching by checking the kernel version and, if available, confirming the specific commit addressing pointer validation in SOF driver code.

Detection guidance

Monitor kernel logs for divide-by-zero exceptions, kernel panics, or audio subsystem crashes correlated with audio stream operations. On affected systems, look for system calls to audio ioctl handlers (ALSA, PulseAudio, or audio API calls) followed by kernel faults. Security monitoring tools should flag unexpected audio subsystem access patterns from untrusted processes. Endpoint Detection and Response (EDR) solutions can detect process behavior attempting to interact with audio devices in abnormal ways. Kernel-level auditing (auditd) can log audio-related system calls, helping identify attack patterns post-incident.

Why prioritize this

While CVE-2026-46179 carries a MEDIUM severity score (5.5) and does not enable privilege escalation or data theft, it poses a meaningful availability risk in environments where local audio access is granted to multiple users or where untrusted workloads run on the same system. Organizations should prioritize patching based on: (1) whether ASoC SOF driver is in use, (2) how many local users or containers have audio access, and (3) the criticality of audio-dependent services. Desktop and audio workstation environments should patch promptly; server-only deployments without audio subsystem use are lower priority.

Risk score, explained

The CVSS 3.1 score of 5.5 (MEDIUM) reflects a denial-of-service impact with low attack complexity and low privilege requirement, limited to local attack vector. The score does not capture privilege escalation or data exposure, which keeps it in the MEDIUM range despite the straightforward exploitability. In environments with high local user/container density or audio-dependent workflows, the business risk may warrant treating this as higher priority than the base score alone suggests.

Frequently asked questions