# CVE-2026-20586: MediaTek vdec out of bounds write

Source: https://junglewise.ai/threats/cve-2026-20586-in-vdec-there-is-a-possible-out-of-bounds-write-due-to-a-missing  
Publisher: Junglewise Threat Intelligence, https://junglewise.ai/threats  
Published: 2026-10-05. Updated: 2026-10-05  
License: CC BY 4.0 with a link back

CVE-2026-20586 · Severity: high · CVSS 8.8 · Published 2026-10-05

MediaTek's vdec component, used in smartphone and IoT chipsets for video decoding, contains a missing bounds check that allows an out-of-bounds write. An attacker could exploit this during video playback to escalate privileges and take control of the device, requiring only user interaction such as opening a malicious video file.

Vendors: [MediaTek](https://junglewise.ai/threats/vendors/mediatek).

## Quick answers

**Is CVE-2026-20586 exploited in the wild?** No. Junglewise Threat Intelligence has no report of CVE-2026-20586 being exploited in the wild.

**How severe is CVE-2026-20586?** High severity, with a CVSS score of 8.8, published 5 October 2026.

**Which products and versions are affected?** MediaTek Dimensity chipsets MT2716, MT2735, MT2737, MT6813, MT6815, MT6833, MT6835, MT6853, MT6855, MT6858, MT6873, MT6875, MT6877, MT6878, MT6879, MT6880, MT6881, MT6883, MT6885, MT6886, MT6889, MT6890, MT6891, MT6893, MT6895, MT6896.

**Is there a fix for CVE-2026-20586?** No fixed version is recorded yet. Check the vendor's advisory in the references below. If you run it, Junglewise drafts a mitigation that fits your setup and applies it once you approve, with senior security engineers behind it.

**How is CVE-2026-20586 attacked?** It is attacked over the network, in device firmware.

**Am I affected by CVE-2026-20586?** Check whether you run MediaTek Dimensity chipsets at an affected version. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.

## Technical details

The vulnerability is an out-of-bounds write (CWE-787) in the vdec (video decoder) component due to a missing bounds check. Exploitation requires user interaction (e.g., viewing malicious video content) but no additional execution privileges, and can lead to remote privilege escalation across multiple MediaTek chipsets. A patch is available via ALPS11383899.

## Affected products

- MediaTek Dimensity chipsets MT2716, MT2735, MT2737, MT6813, MT6815, MT6833, MT6835, MT6853, MT6855, MT6858, MT6873, MT6875, MT6877, MT6878, MT6879, MT6880, MT6881, MT6883, MT6885, MT6886, MT6889, MT6890, MT6891, MT6893, MT6895, MT6896

## Timeline

- 2026-10-05: disclosed

## References

- [https://www.mediatek.com/product-security-bulletin/October-2026](https://www.mediatek.com/product-security-bulletin/October-2026)

## Related threats

- [MediaTek mtee privilege escalation due to missing bounds check](https://junglewise.ai/threats/cve-2026-20588-in-mtee-there-is-a-possible-escalation-of-privilege-due-to-a)