# CVE-2021-47108: linux: In the Linux kernel, the following vulnerability has been resolved:  drm/mediatek: hdmi: Perform NULL pointer check f...

CVE-2021-47108 is fixed in linux on 1 platform, first by DEBIAN-CVE-2021-47108, released March 4, 2024. It is not reported as exploited. Patch Radar priority: Routine.

- Web page: https://patchblox.com/security/cve/CVE-2021-47108
- Priority: Routine
- CVSS: 5.5 (medium)
- EPSS: 0.0020
- CISA KEV: not listed
- Exploited (vendor report): no
- Publicly disclosed: no
- Published: Mar 4, 2024

## Description

In the Linux kernel, the following vulnerability has been resolved:  drm/mediatek: hdmi: Perform NULL pointer check for mtk_hdmi_conf  In commit 41ca9caaae0b ("drm/mediatek: hdmi: Add check for CEA modes only") a check for CEA modes was added to function mtk_hdmi_bridge_mode_valid() in order to address possible issues on MT8167; moreover, with commit c91026a938c2 ("drm/mediatek: hdmi: Add optional limit on maximal HDMI mode clock") another similar check was introduced.  Unfortunately though, at the time of writing, MT8173 does not provide any mtk_hdmi_conf structure and this is crashing the kernel with NULL pointer upon entering mtk_hdmi_bridge_mode_valid(), which happens as soon as a HDMI cable gets plugged in.  To fix this regression, add a NULL pointer check for hdmi->conf in the said function, restoring HDMI functionality and avoiding NULL pointer kernel panics.

## Where it's fixed

| Platform | Product | Fixed in | Fix | Released |
|---|---|---|---|---|
| Linux | linux Debian 12.15 (bookworm) | 5.15.15-1 | [DEBIAN-CVE-2021-47108](https://patchblox.com/security/data/fix/linux/debian-cve-2021-47108.md) | Mar 4, 2024 |
| Linux | linux Debian 13.5 (trixie) | 5.15.15-1 | [DEBIAN-CVE-2021-47108](https://patchblox.com/security/data/fix/linux/debian-cve-2021-47108.md) | Mar 4, 2024 |
| Linux | linux Debian 14 | 5.15.15-1 | [DEBIAN-CVE-2021-47108](https://patchblox.com/security/data/fix/linux/debian-cve-2021-47108.md) | Mar 4, 2024 |

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