CVE-2026-20555 MediaTek, Inc. CVE debrief

Who should care

Defenders and security teams responsible for Modem and base station security should assess exposure and prioritize patching. This includes teams managing network infrastructure, security operations, and vulnerability management. They should verify affected versions, apply patches, and monitor for rogue base stations to mitigate potential operational impacts. The vulnerability's impact on operational security could be significant if exploited, especially in

Why it matters

Defenders should care about CVE-2026-20555 because it could lead to remote denial of service in Modem if exploited. Verification of affected versions and patching are crucial.

• Remote denial of service requires verification
• Potential exposure if connected to rogue base stations

Technical summary

A possible out of bounds read in Modem due to a missing bounds check could lead to remote denial of service. The vulnerability is triggered when a UE connects to a rogue base station controlled by the attacker. User interaction is not needed for exploitation. The technical impact is significant, as it allows for remote denial of service without requiring additional execution privileges. Defenders should focus on verifying affected versions and applying patches from the vendor to mitigate this vulnerability. The source-grounded technical framing indicates a high severity level due to the potential for remote exploitation.

Defensive priority

Defenders should prioritize verifying affected versions and applying patches from the vendor.

Recommended defensive actions

• Verify affected versions with the vendor
• Apply patches from the vendor
• Monitor for rogue base stations
• Review compensating controls for exposed systems while remediation is scheduled and verified
• Check relevant monitoring, detection, and logs for exposed assets that need extra review
• Track exceptions, retest remediated assets, and close the item only after evidence is documented
• Confirm whether affected product deployments exist in managed environments and assign an owner for follow-up

Evidence notes

Evidence from Mediatek indicates a possible out of bounds read in Modem due to a missing bounds check. The evidence is based on Mediatek's official advisory and CVE record. Defenders should verify affected versions and apply patches from the vendor. The source confidence is high, but the exact scope of affected products and versions may require further verification.

Sources and references

Methodology and review provenance

AI-assisted synthesis based on stored public vulnerability evidence. System validation, approval state, and publication status do not by themselves establish human review of this revision. PatchSiren helps prioritize defensive review and does not prove exposure or remediation on any system.