Quick answers
- Is CVE-2026-20556 exploited in the wild?
- No. Junglewise Threat Intelligence has no report of CVE-2026-20556 being exploited in the wild.
- How severe is CVE-2026-20556?
- Informational severity, published 2 November 2026.
- Which products and versions are affected?
- MediaTek Modem.
- Is there a fix for CVE-2026-20556?
- 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-2026-20556 attacked?
- It is attacked over the network or from the adjacent network, in device firmware.
- Am I affected by CVE-2026-20556?
- 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
An out-of-bounds write vulnerability exists in the MediaTek modem due to missing bounds checking. The attack is triggered over-the-air by a rogue base station that the user equipment connects to; no additional privileges or user interaction are required. Successful exploitation results in remote escalation of privilege, granting the attacker kernel-level control of the modem and potentially the host device.
Affected products
- MediaTek Modem
Timeline
- 2026-11-02: disclosed