# CVE-2026-20431: MediaTek Chipset denial of service in Modem

Source: https://junglewise.ai/threats/cve-2026-20431-mediatek-chipset-denial-of-service-in-modem  
Publisher: Junglewise Threat Intelligence, https://junglewise.ai/threats  
Published: 2026-04-07. Updated: 2026-07-25  
License: CC BY 4.0 with a link back

CVE-2026-20431 · Severity: medium · CVSS 6.5 · Published 2026-04-07

A vulnerability in certain MediaTek chipsets could allow an attacker to crash a mobile device's modem, leading to a loss of cellular connectivity. This occurs when a device connects to a malicious base station (rogue cell tower) controlled by the attacker. An exploit would result in a denial of service, preventing the user from making calls or using mobile data until the system is recovered.

## Quick answers

**Is CVE-2026-20431 exploited in the wild?** No. Junglewise Threat Intelligence has no report of CVE-2026-20431 being exploited in the wild.

**How severe is CVE-2026-20431?** Medium severity, with a CVSS score of 6.5, published 7 April 2026.

**Which products and versions are affected?** MediaTek MT6813; MediaTek MT6815; MediaTek MT6835; MediaTek MT6878; and 15 more.

**Is there a fix for CVE-2026-20431?** 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-2026-20431 attacked?** It is attacked from the adjacent network, in device firmware.

**Am I affected by CVE-2026-20431?** Check whether anything you run is named in the advisory. 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

A logic error in the MediaTek modem firmware (CWE-770) leads to a system crash when the User Equipment (UE) interacts with a rogue base station. The vulnerability is exploitable via an adjacent network vector without requiring authentication or user interaction. An attacker in physical proximity can deploy a rogue base station to trigger a remote denial of service (DoS) on affected devices. MediaTek has released Patch ID MOLY01106496 to address this issue across multiple chipset models including MT68xx, MT69xx, and MT8xxx series.

## Affected products

- MediaTek MT6813
- MediaTek MT6815
- MediaTek MT6835
- MediaTek MT6878
- MediaTek MT6897
- MediaTek MT6899
- MediaTek MT6986
- MediaTek MT6991
- MediaTek MT6993
- MediaTek MT8668
- MediaTek MT8676
- MediaTek MT8678
- MediaTek MT8755
- MediaTek MT8775
- MediaTek MT8792
- MediaTek MT8793
- MediaTek MT8863
- MediaTek MT8873
- MediaTek MT8883

## Timeline

- 2026-04-07: advisory: MediaTek published the security bulletin
- 2026-04-07: disclosed: CVE published to NVD

## References

- [https://corp.mediatek.com/product-security-bulletin/April-2026](https://corp.mediatek.com/product-security-bulletin/April-2026)