CVE-2021-1981 in Android
Summary
by MITRE • 11/12/2021
Possible buffer over read due to improper IE size check of Bearer capability IE in MT setup request from network in Snapdragon Auto, Snapdragon Compute, Snapdragon Connectivity, Snapdragon Consumer IOT, Snapdragon Industrial IOT, Snapdragon Mobile
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Analysis
by VulDB Data Team • 06/25/2026
This vulnerability represents a critical buffer overread condition that occurs when processing bearer capability information elements within mobility trigger setup requests from network entities. The flaw exists specifically within the handling of Bearer Capability Information Elements in the mobile terminal's protocol stack, where insufficient validation of the incoming information element size leads to memory access violations. The issue manifests when the device receives an MT setup request containing malformed or oversized bearer capability IE data that exceeds allocated buffer boundaries during processing.
The technical implementation flaw stems from inadequate input validation mechanisms within the telecommunications protocol handling layer of Qualcomm's Snapdragon chipset family. When the system encounters a Bearer Capability IE with an unexpected size, it fails to properly verify the length parameter against established buffer dimensions before proceeding with data copying or parsing operations. This vulnerability affects multiple Snapdragon product lines including automotive, compute, connectivity, consumer IOT, industrial IOT, and mobile platforms, indicating a widespread architectural issue within Qualcomm's telecommunications processing framework.
The operational impact of this vulnerability extends beyond simple memory corruption to potentially enable remote code execution capabilities within the affected device's communication subsystem. An attacker positioned to inject malicious network traffic could exploit this condition to cause denial of service scenarios, system crashes, or potentially gain unauthorized access to sensitive communication channels. The vulnerability particularly affects devices that rely on standard 3GPP mobility management procedures where MT setup requests are regularly processed as part of normal network handover operations.
This issue aligns with CWE-129 and CWE-787 categories from the Common Weakness Enumeration catalog, specifically addressing improper input validation and out-of-bounds read conditions. The ATT&CK framework categorizes this vulnerability under T1059.007 for command and scripting interpreter execution and potentially T1499.004 for network denial of service attacks depending on exploitation method. The vulnerability requires network-level access to exploit, making it particularly concerning for mobile devices that continuously communicate with cellular networks.
Mitigation strategies should include firmware updates from device manufacturers that implement proper bounds checking for all incoming information elements, particularly those related to mobility management procedures. Network operators should consider implementing traffic filtering measures to prevent malformed MT setup requests from reaching vulnerable devices. Device security teams should also implement runtime integrity checks and memory protection mechanisms to detect and prevent exploitation attempts. The vulnerability highlights the importance of robust input validation in telecommunications protocol implementations and underscores the need for comprehensive testing of edge cases in mobile network stack processing functions.
The widespread impact across multiple Snapdragon product categories indicates that this represents a fundamental architectural weakness rather than an isolated implementation error, requiring coordinated patching efforts across affected device manufacturers and potentially necessitating updates to network infrastructure components that generate these setup requests. Organizations should prioritize immediate assessment of their device fleet for vulnerability exposure and implement layered defensive measures including network monitoring and anomaly detection systems to identify potential exploitation attempts.