Cloudanix VulnDB

CVE-2026-63838

None

CVSS

—

EPSS

0.2%

Published

Jul 19, 2026

CISA due date

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Cloudanix analysis

Schedule a fix SSVC: Track

A bug in Linux audio handling code could let a program on the same computer read or write memory it should not, potentially crashing the system or allowing misuse.

Exploitation
Local Privilege
Attacker needs
Local User
Complexity
Moderate
Impact
Privilege Gain
Component
OS kernel
Class
Buffer Overflow
Remediation
Upgrade
Effort
Medium
Patch risk
Low

What it actually does

Flawed boundary check on zero-initialized component_dais[] array in rsnd driver allows loop to dereference RSND_MAX_COMPONENT index, resulting in out-of-bounds kernel memory access.

Why it matters to the business

May cause kernel crashes, denial of service, or limited code execution on affected Linux audio systems; low likelihood reduces immediate operational risk but still requires patching to maintain kernel integrity.

How an attack unfolds

An attacker with local access loads or configures the rsnd sound driver on supported Renesas hardware, supplies crafted device-tree nodes to rsnd_dai_of_node(), and triggers the loop that reads past the intended array end due to the incomplete boundary guard.

How to fix it

Update to a Linux kernel containing the fix for the rsnd component_dais boundary check; rebuild and deploy the kernel image on affected systems; verify the updated driver source contains a corrected loop guard that keeps the final array element zero.

How to confirm the fix worked

Confirm kernel source contains the resolved rsnd_dai_of_node logic; boot test system with the driver and inspect that component_dais accesses stay within RSND_MAX_COMPONENT; run static analysis or the original SVACE tool against the patched code.

Typical attack path

  1. Obtain local shell or loadable module privileges on target Linux system
  2. Ensure rsnd ASoC driver is present and bound to hardware
  3. Provide malicious device-tree or ALSA configuration that populates component_dais beyond intended limit
  4. Trigger audio initialization path that executes the faulty loop
  5. Observe or leverage resulting out-of-bounds read for denial of service or further exploitation

How to detect it

Review kernel logs for oops or panic messages referencing rsnd_dai_of_node or component_dais array access; correlate with ALSA or device-tree initialization events on systems exposing the rsnd driver.

What your security team should do

  • Prioritize kernel upgrade on any systems using the rsnd driver within standard change windows
  • Monitor upstream stable kernel releases for the backported fix
  • Restrict local user access on audio-capable embedded or server systems until patched
  • Include the rsnd driver in future kernel configuration reviews for similar array-handling patterns

The record

In the Linux kernel, the following vulnerability has been resolved: ASoC: rsnd: Fix potential out-of-bounds access of component_dais[] component_dais[RSND_MAX_COMPONENT] is initially zero-initialized and later populated in rsnd_dai_of_node(). However, the existing boundary check: if (i >= RSND_MAX_COMPONENT) does not guarantee that the last valid element remains zero. As a result, the loop can rely on component_dais[RSND_MAX_COMPONENT] being zero, which may lead to an out-of-bounds access. Found by Linux Verification Center (linuxtesting.org) with SVACE.

Affected packages

Ecosystem Package Introduced Fixed