# CVE-2024-56685: ASoC: mediatek: Check num_codecs is not zero to avoid panic during probe > A missing check in the MediaTek ASoC driver causes a null pointer dereference and kernel panic during probe if specific device tree configurations are used. - **Severity:** Medium 5.5 (`CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H`) - **Exploited in the wild:** Not known - **Login needed:** Any signed-in user - **Attackable:** Local or same network only - **Victim action needed:** Not needed - **Fix available:** Yes - **Published:** 28 Dec 2024 - **Updated:** 11 May 2026 - **Also known as:** BELL-CVE-2024-56685, DEBIAN-CVE-2024-56685, GHSA-54qc-m2ph-jw4r, UBUNTU-CVE-2024-56685 ## What is CVE-2024-56685? CVE-2024-56685 is a medium-severity vulnerability in Linux kernel, published on 28 Dec 2024. It can only be exploited from the same machine or local network, with no action from the victim. ### Official description In the Linux kernel, the following vulnerability has been resolved: ASoC: mediatek: Check num_codecs is not zero to avoid panic during probe Following commit 13f58267cda3 ("ASoC: soc.h: don't create dummy Component via COMP_DUMMY()"), COMP_DUMMY() became an array with zero length, and only gets populated with the dummy struct after the card is registered. Since the sound card driver's probe happens before the card registration, accessing any of the members of a dummy component during probe will result in undefined behavior. This can be observed in the mt8188 and mt8195 machine sound drivers. By omitting a dai link subnode in the sound card's node in the Devicetree, the default uninitialized dummy codec is used, and when its dai_name pointer gets passed to strcmp() it results in a null pointer dereference and a kernel panic. In addition to that, set_card_codec_info() in the generic helpers file, mtk-soundcard-driver.c, will populate a dai link with a dummy codec when a dai link node is present in DT but with no codec property. The result is that at probe time, a dummy codec can either be uninitialized with num_codecs = 0, or be an initialized dummy codec, with num_codecs = 1 and dai_name = "snd-soc-dummy-dai". In order to accommodate for both situations, check that num_codecs is not zero before accessing the codecs' fields but still check for the codec's dai name against "snd-soc-dummy-dai" as needed. While at it, also drop the check that dai_name is not null in the mt8192 driver, introduced in commit 4d4e1b6319e5 ("ASoC: mediatek: mt8192: Check existence of dai_name before dereferencing"), as it is actually redundant given the preceding num_codecs != 0 check. Weakness: CWE-908 (Use of Uninitialized Resource) ## Which versions are affected by CVE-2024-56685? It affects 1 product. Products: Linux kernel. ## How do I fix CVE-2024-56685? Apply the vendor's patch. ## Is CVE-2024-56685 being exploited? There is no known exploitation of CVE-2024-56685 in the wild and no public exploit code. ## Other vulnerabilities in Linux kernel - [CVE-2026-53266](https://insights.sbomify.com/CVE-2026-53266/): Linux Kernel Out-of-Bounds Write (high 8.8, exploited in the wild) - [CVE-2013-6282](https://insights.sbomify.com/CVE-2013-6282/): Linux Kernel Improper Input Validation (high 8.8, exploited in the wild) - [CVE-2022-0185](https://insights.sbomify.com/CVE-2022-0185/): Linux Kernel Heap-Based Buffer Overflow (high 8.4, exploited in the wild) - [CVE-2013-2094](https://insights.sbomify.com/CVE-2013-2094/): Linux Kernel Privilege Escalation (high 8.4, exploited in the wild) - [CVE-2026-53362](https://insights.sbomify.com/CVE-2026-53362/): Linux Kernel Unspecified (high 7.8, exploited in the wild) ## Fix prompt for AI coding agents ```text Check this codebase for CVE-2024-56685 and fix it if it is affected. What it is: CVE-2024-56685 is a medium-severity vulnerability in Linux kernel, published on 28 Dec 2024. It can only be exploited from the same machine or local network, with no action from the victim. Exploitation: There is no known exploitation of CVE-2024-56685 in the wild and no public exploit code. Affected product: Linux kernel. No package-level version data is available, so check the vendor advisory linked from the reference page. Task: 1. Search the dependency manifests and lockfiles (for example package.json, package-lock.json, requirements.txt, poetry.lock, uv.lock, pom.xml, build.gradle, go.mod, Cargo.lock, Gemfile.lock) and any Dockerfiles for the affected packages, including transitive dependencies. 2. If an affected version is in use, upgrade it to the fixed version for its release line with the project's package manager, so the lockfile is regenerated. Prefer the smallest upgrade that fixes it. 3. If there is no fix, or the upgrade would break the build, do not guess: explain the risk and the safest workaround instead. 4. Run the tests and summarise what changed and why. 5. If nothing in the project is affected, say so and change nothing. Reference: https://insights.sbomify.com/CVE-2024-56685/ (Markdown: https://insights.sbomify.com/CVE-2024-56685/index.md) ``` ## Sources - CVE record: https://www.cve.org/CVERecord?id=CVE-2024-56685 - NVD: https://nvd.nist.gov/vuln/detail/CVE-2024-56685 - OSV: https://osv.dev/vulnerability/CVE-2024-56685 --- From sbomify Insights: https://insights.sbomify.com/CVE-2024-56685/ Summaries are generated and may contain mistakes; the official description above is the record.