CVE-2026-20545 MediaTek, Inc. CVE debrief

Who should care

Defenders and security teams responsible for managing and securing Modem components should assess exposure and prioritize patching based on the vendor bulletin and CVE details. This includes teams handling vulnerability management, incident response, and those ensuring the security of network infrastructure and UE connections. Security teams should also monitor for potential exploitation attempts and review compensating controls for exposed systems.

Why it matters

CVE-2026-20545 is a possible out of bounds write in Modem due to a missing bounds check. Defenders should prioritize verifying and applying patches, assessing exposure, and monitoring for potential exploitation attempts.

• Remote escalation of privilege possible if UE connects to rogue base station
• No user interaction needed for exploitation
• Patching and verification recommended to prevent potential exploitation

Technical summary

A possible out of bounds write due to a missing bounds check in Modem could lead to remote escalation of privilege if a UE has connected to a rogue base station controlled by the attacker. User interaction is not needed for exploitation. The issue is identified as MSV-9811 with patches available as MOLY01879158 / MOLY01774038. Technical details indicate a missing bounds check in the Modem component, which could allow attackers to execute remote escalation of privilege attacks. Defenders should prioritize verifying and applying patches, assessing exposure, and monitoring for potential exploitation attempts.

Defensive priority

Defenders should prioritize verifying and applying patches from the vendor, assessing exposure in their environment, and monitoring for potential exploitation attempts.

Recommended defensive actions

• Verify and apply patches from the vendor
• Assess exposure in your environment
• Monitor for potential exploitation attempts
• Review compensating controls for exposed systems
• Check relevant monitoring, detection, and logs for exposed assets
• 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

The CVE record and vendor bulletin provide limited information about the vulnerability and its potential impact. Further verification and testing may be necessary to fully understand the vulnerability and its effects.

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.