# CVE-2026-20525: MediaTek Modem denial of service due to improper input validation

Source: https://junglewise.ai/threats/cve-2026-20525-in-modem-there-is-a-possible-system-crash-due-to-improper-input  
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-2026-20525 · Severity: medium · CVSS 5.3 · Published 2026-10-05

MediaTek modems in smartphones and IoT devices can crash when exposed to specially crafted signals from a rogue base station, disrupting cellular connectivity without requiring any user action or attacker privileges. An attacker within radio range can trigger a remote denial of service by impersonating a legitimate cellular network, causing affected devices to lose network access until reboot.

Technologies: [MediaTek Modem](https://junglewise.ai/threats/technologies/modem). Vendors: [MediaTek](https://junglewise.ai/threats/vendors/mediatek).

## Quick answers

**Is CVE-2026-20525 exploited in the wild?** No. Junglewise Threat Intelligence has no report of CVE-2026-20525 being exploited in the wild.

**How severe is CVE-2026-20525?** Medium severity, with a CVSS score of 5.3, published 5 October 2026.

**Which products and versions are affected?** MediaTek Modem 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-2026-20525?** 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-2026-20525 attacked?** It is attacked from the adjacent network or over the network, in device firmware.

**Am I affected by CVE-2026-20525?** Check whether you run MediaTek Modem 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

A modem firmware component fails to properly validate input from base station signals, leading to a system crash (denial of service). The vulnerability is triggered via an adjacent network attack vector when a UE (user equipment) connects to an attacker-controlled rogue base station; no additional execution privileges or user interaction are required. The flaw is in input validation logic, allowing an unauthenticated remote attacker to cause device unavailability.

## Affected products

- MediaTek Modem 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
- 2026-10-05: advisory: MediaTek Product Security Bulletin published; patches available to OEMs since at least two months prior

## References

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

## Related threats

- [MediaTek Modem privilege escalation via permissions bypass](https://junglewise.ai/threats/cve-2026-68591-in-modem-there-is-a-possible-escalation-of-privilege-due-to-a)
- [MediaTek Modem out-of-bounds write privilege escalation](https://junglewise.ai/threats/cve-2026-68589-in-modem-there-is-a-possible-out-of-bounds-write-due-to-a-missing)
- [MediaTek Modem integer overflow denial of service](https://junglewise.ai/threats/cve-2026-68588-in-modem-there-is-a-possible-way-for-xxx-to-xxxxx-due-to-an)
- [MediaTek Modem logic error denial of service](https://junglewise.ai/threats/cve-2026-20600-in-modem-there-is-a-possible-application-crash-due-to-a-logic)
- [MediaTek Modem privilege escalation due to missing permission check](https://junglewise.ai/threats/cve-2026-20599-in-modem-there-is-a-possible-escalation-of-privilege-due-to-a)