# CVE-2026-20493: MediaTek Wi-Fi out-of-bounds write

Source: https://junglewise.ai/threats/cve-2026-20493-mediatek-wi-fi-out-of-bounds-write  
Publisher: Junglewise Threat Intelligence, https://junglewise.ai/threats  
Published: 2026-08-03. Updated: 2026-09-25  
License: CC BY 4.0 with a link back

CVE-2026-20493 · Severity: medium · CVSS 4.4 · Published 2026-08-03

MediaTek Wi-Fi chipsets contain a memory safety vulnerability that allows a local attacker with system privileges to crash the device or potentially cause data corruption. This affects many smartphones, tablets, and IoT devices that rely on MediaTek's wireless components. An attacker who has already gained system-level access could exploit this to disable network functionality or destabilize the device.

Technologies: [MediaTek Mt6890](https://junglewise.ai/threats/technologies/mt6890), [MediaTek Mt6890 Firmware](https://junglewise.ai/threats/technologies/mt6890-firmware), [MediaTek MT6988](https://junglewise.ai/threats/technologies/mt6988), [MediaTek Mt6988 Firmware](https://junglewise.ai/threats/technologies/mt6988-firmware), [MediaTek MT6990](https://junglewise.ai/threats/technologies/mt6990), [MediaTek Mt6990 Firmware](https://junglewise.ai/threats/technologies/mt6990-firmware). Vendors: [MediaTek](https://junglewise.ai/threats/vendors/mediatek).

## Quick answers

**Is CVE-2026-20493 exploited in the wild?** No. Junglewise Threat Intelligence has no report of CVE-2026-20493 being exploited in the wild.

**How severe is CVE-2026-20493?** Medium severity, with a CVSS score of 4.4, published 3 August 2026.

**Which products and versions are affected?** MediaTek Wi-Fi <UNKNOWN>.

**Is there a fix for CVE-2026-20493?** 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-2026-20493 attacked?** It is attacked with local access, in device firmware.

**Am I affected by CVE-2026-20493?** Check whether you run MediaTek Mt6890, MediaTek Mt6890 Firmware, MediaTek MT6988 or one of the others listed 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

This is an out-of-bounds write vulnerability in the Wi-Fi subsystem caused by missing bounds checking (CWE-787). The vulnerability requires local access and system privilege level, meaning an attacker must have already compromised the device or be an unprivileged process that can escalate privileges. No user interaction is needed once these preconditions are met. Exploitation can lead to local denial of service through memory corruption. MediaTek has issued patches (Patch ID: BORA00154903) and the vulnerability is tracked under Issue ID MSV-7575. There is currently no evidence of active exploitation in the wild.

## Affected products

- MediaTek Wi-Fi <UNKNOWN>

## Timeline

- 2026-08-03: disclosed
- 2026-08-03: advisory: MediaTek security bulletin published; patches available for at least 2 months prior

## References

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

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