Qualcomm Memory Corruption Vulnerability (CVE-2026-21371)

CVE-2026-21371 is a memory corruption vulnerability present in certain Qualcomm products. The vulnerability stems from insufficient size validation when retrieving an output buffer. This flaw can lead to a buffer over-read (CWE-126), potentially allowing a malicious actor with local access to read sensitive information from memory or execute arbitrary code. The vulnerability was reported by Qualcomm and affects undisclosed products. Publicly available information is limited, making it difficult to assess the scope of the vulnerability and precise exploitation scenarios. Defenders should monitor for unexpected memory access patterns in Qualcomm-based systems.

Attack Chain

1. An attacker gains local access to a vulnerable device running a Qualcomm chipset.
2. The attacker triggers a specific function call that involves retrieving an output buffer.
3. Due to the insufficient size validation, the output buffer retrieval process reads beyond the allocated memory boundary (CWE-126).
4. The memory over-read allows the attacker to access sensitive data stored in adjacent memory regions.
5. The attacker analyzes the leaked memory contents to identify exploitable information, such as pointers, cryptographic keys, or other sensitive data.
6. Using the gained knowledge, the attacker crafts a malicious input to further exploit the vulnerability and achieve arbitrary code execution.
7. The attacker executes malicious code to gain elevated privileges or compromise the system.

Impact

A successful exploit of CVE-2026-21371 could result in information disclosure, where an attacker can read sensitive data from device memory. In a more severe scenario, it could lead to arbitrary code execution, potentially allowing an attacker to gain complete control of the affected device. The impact is significant for devices using vulnerable Qualcomm chipsets, potentially affecting a large number of mobile devices and other embedded systems.

Recommendation

• Monitor systems for unexpected memory access patterns, specifically buffer over-reads, using endpoint detection and response (EDR) solutions.
• Apply patches and updates released by Qualcomm for CVE-2026-21371 as soon as they become available. Refer to the Qualcomm security bulletin referenced in this brief.
• Deploy the Sigma rule “Detect Potential Buffer Over-Read Exploitation” to identify suspicious process creation events associated with abnormal memory access patterns.
• Enable process monitoring and auditing on systems utilizing Qualcomm chipsets to track memory access operations and identify potential exploitation attempts.