# CVE-2026-20554: MediaTek Modem system crash due to missing bounds check

Source: https://junglewise.ai/threats/cve-2026-20554-in-modem-there-is-a-possible-system-crash-due-to-a-missing-bounds  
Publisher: Junglewise Threat Intelligence, https://junglewise.ai/threats  
Published: 2026-11-02. Updated: 2026-11-02  
License: CC BY 4.0 with a link back

CVE-2026-20554 · Severity: info · Published 2026-11-02

MediaTek modems are wireless communication processors used in smartphones and mobile devices. A flaw in bounds checking could allow an attacker controlling a rogue cellular base station to crash the modem and escalate privileges on the device. This attack requires the victim to connect to the attacker's fake base station but does not require any special permissions on the device itself.

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

## Quick answers

**Is CVE-2026-20554 exploited in the wild?** No. Junglewise Threat Intelligence has no report of CVE-2026-20554 being exploited in the wild.

**How severe is CVE-2026-20554?** Informational severity, published 2 November 2026.

**Which products and versions are affected?** MediaTek Modem.

**Is there a fix for CVE-2026-20554?** 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-2026-20554 attacked?** It is attacked over the network, in device firmware.

**Am I affected by CVE-2026-20554?** Check whether you run MediaTek Modem. 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 a missing bounds check in MediaTek modem firmware that leads to a system crash (denial of service). An attacker can trigger privilege escalation by hosting a malicious base station that the UE (user equipment) connects to. The attack vector is network-based and requires user interaction in the form of the device connecting to the rogue base station; no additional execution privileges are needed on the target.

## Affected products

- MediaTek Modem

## Timeline

- 2026-11-02: disclosed

## References

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