# CVE-2026-20577: MediaTek Modem permission bypass in privileged context

Source: https://junglewise.ai/threats/cve-2026-20577-in-modem-there-is-a-possible-permission-bypass-due-to-a  
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-2026-20577 · Severity: info · Published 2026-11-02

A permission bypass vulnerability in MediaTek's modem firmware could allow a local attacker with system-level privileges to cause a denial of service. While an attacker must already have obtained elevated system access, no user interaction is required to trigger the vulnerability. This affects cellular modems in smartphones and other connected devices.

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

## Quick answers

**Is CVE-2026-20577 exploited in the wild?** No. Junglewise Threat Intelligence has no report of CVE-2026-20577 being exploited in the wild.

**How severe is CVE-2026-20577?** Informational severity, published 2 November 2026.

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

**Is there a fix for CVE-2026-20577?** 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-2026-20577 attacked?** It is attacked with local access, in device firmware.

**Am I affected by CVE-2026-20577?** 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 permissions bypass in the MediaTek Modem that could lead to local denial of service. It requires the attacker to already possess System privilege level and is exploitable without user interaction. The exact mechanism and affected modem models are not specified in the advisory; remediation patches have been provided to device OEMs.

## 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)