CVE-2026-20538

Analyzed Analyzed - Analysis Complete

Out of Bounds Read in Modem Due to Missing Permission Check

Publication date: 2026-10-05

Last updated on: 2026-10-09

Assigner: MediaTek, Inc.

Description

In Modem, there is a possible out of bounds read due to a missing permission check. This could lead to remote denial of service, if a UE has connected to a rogue base station controlled by the attacker, with no additional execution privileges needed. User interaction is not needed for exploitation. Patch ID: MOLY01774038; Issue ID: MSV-8914.

CVSS Scores

EPSS Scores

Probability:
Percentile:

Meta Information

Published

2026-10-05

Last Modified

2026-10-09

Generated

2026-10-19

AI Q&A

2026-10-05

EPSS Evaluated

2026-10-18

NVD

CVE-2026-20538

EUVD

EUVD-2026-92185

Affected Vendors & Products

Vendor	Product	Version / Range
mediatek	mt2716_firmware	*
mediatek	mt2735_firmware	*
mediatek	mt2737_firmware	*
mediatek	mt6739_firmware	*
mediatek	mt6761_firmware	*
mediatek	mt6762_firmware	*
mediatek	mt6763_firmware	*
mediatek	mt6765_firmware	*
mediatek	mt6767_firmware	*
mediatek	mt6768_firmware	*
mediatek	mt6769_firmware	*
mediatek	mt6771_firmware	*
mediatek	mt6779_firmware	*
mediatek	mt6781_firmware	*
mediatek	mt6783_firmware	*
mediatek	mt6785_firmware	*
mediatek	mt6789_firmware	*
mediatek	mt6813_firmware	*
mediatek	mt6815_firmware	*
mediatek	mt6833_firmware	*
mediatek	mt6835_firmware	*
mediatek	mt6853_firmware	*
mediatek	mt6855_firmware	*
mediatek	mt6858_firmware	*
mediatek	mt6873_firmware	*
mediatek	mt6875_firmware	*
mediatek	mt6877_firmware	*
mediatek	mt6878_firmware	*
mediatek	mt6879_firmware	*
mediatek	mt6880_firmware	*
mediatek	mt6881_firmware	*
mediatek	mt6883_firmware	*
mediatek	mt6885_firmware	*
mediatek	mt6886_firmware	*
mediatek	mt6889_firmware	*
mediatek	mt6890_firmware	*
mediatek	mt6891_firmware	*
mediatek	mt6893_firmware	*
mediatek	mt6895_firmware	*
mediatek	mt6896_firmware	*
mediatek	mt6897_firmware	*
mediatek	mt6899_firmware	*
mediatek	mt6980_firmware	*
mediatek	mt6982_firmware	*
mediatek	mt6983_firmware	*
mediatek	mt6985_firmware	*
mediatek	mt6986_firmware	*
mediatek	mt6988_firmware	*
mediatek	mt6989_firmware	*
mediatek	mt6990_firmware	*
mediatek	mt6991_firmware	*
mediatek	mt6993_firmware	*
mediatek	mt8666_firmware	*
mediatek	mt8667_firmware	*
mediatek	mt8668_firmware	*
mediatek	mt8673_firmware	*
mediatek	mt8675_firmware	*
mediatek	mt8676_firmware	*
mediatek	mt8678_firmware	*
mediatek	mt8755_firmware	*
mediatek	mt8765_firmware	*
mediatek	mt8766_firmware	*
mediatek	mt8766r_firmware	*
mediatek	mt8768_firmware	*
mediatek	mt8771_firmware	*
mediatek	mt8775_firmware	*
mediatek	mt8781_firmware	*
mediatek	mt8786_firmware	*
mediatek	mt8788_firmware	*
mediatek	mt8788e_firmware	*
mediatek	mt8789_firmware	*
mediatek	mt8791_firmware	*
mediatek	mt8791t_firmware	*
mediatek	mt8792_firmware	*
mediatek	mt8793_firmware	*
mediatek	mt8795t_firmware	*
mediatek	mt8796_firmware	*
mediatek	mt8797_firmware	*
mediatek	mt8798_firmware	*
mediatek	mt8863_firmware	*
mediatek	mt8873_firmware	*
mediatek	mt8883_firmware	*
mediatek	mt8893_firmware	*

Helpful Resources

Exploitability

CWE

KEV

CWE ID	Description
CWE-126	The product reads from a buffer using buffer access mechanisms such as indexes or pointers that reference memory locations after the targeted buffer.

Attack-Flow Graph

Executive Summary

This vulnerability in Modem allows a remote denial of service due to a missing permission check that causes an out of bounds read. Exploitation requires a UE to connect to a rogue base station controlled by the attacker, with no additional privileges needed and no user interaction required.

Detection Guidance

Detection of CVE-2026-20538 requires monitoring for unusual activity from devices connected to your network, particularly those interacting with a rogue base station. Since this vulnerability involves a missing permission check in the Modem component, network-level detection may be necessary. Check for unexpected modem behavior or crashes in connected user equipment (UE).

Impact Analysis

If exploited, this vulnerability could cause your device to experience a remote denial of service when connected to a malicious base station. This may result in loss of connectivity or service disruption for your device.

Compliance Impact

The provided CVE data does not specify direct impacts on compliance with standards like GDPR or HIPAA. The vulnerability involves a possible out of bounds read in Modem due to a missing permission check, potentially leading to remote denial of service under specific conditions. Without explicit details on data exposure or privacy implications, its compliance impact remains unclear.

Mitigation Strategies

Apply the patch identified as MOLY01774038 to address the missing permission check in the Modem component. Ensure all connected User Equipment (UE) devices are updated to prevent potential remote denial of service via rogue base stations.

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