Cyber Posture

CVE-2026-21371

High

Published: 06 April 2026

Published
06 April 2026
Modified
08 April 2026
KEV Added
Patch
CVSS Score 7.8 CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
EPSS Score 0.0001 0.4th percentile
Risk Priority 16 60% EPSS · 20% KEV · 20% CVSS

Summary

CVE-2026-21371 is a high-severity Buffer Over-read (CWE-126) vulnerability in Qualcomm Aqt1000 Firmware. Its CVSS base score is 7.8 (High).

Operationally, exploitation aligns with the MITRE ATT&CK technique Exploitation for Privilege Escalation (T1068); ranked at the 0.4th percentile by exploit likelihood (below the median); it is not currently listed in the CISA KEV catalog.

The strongest mitigations our analysis identified are NIST 800-53 SI-10 (Information Input Validation) and SI-16 (Memory Protection).

Threat & Defense at a Glance

What attackers do: exploitation maps to Exploitation for Privilege Escalation (T1068). What defenders deploy: see the NIST 800-53 controls recommended below.
Threat & Defense Details

Mitigating Controls (NIST 800-53 r5)AI

prevent

Implements memory protection mechanisms that directly prevent exploitation of buffer over-read vulnerabilities like CVE-2026-21371 caused by insufficient output buffer size validation.

prevent

Requires identification, reporting, and timely remediation of flaws such as CVE-2026-21371 through patches provided in Qualcomm's security bulletin.

prevent

Enforces validation of input parameters, including buffer sizes, to mitigate memory corruption from insufficient size checks in output buffer retrieval.

MITRE ATT&CK Enterprise TechniquesAI

T1068 Exploitation for Privilege Escalation Privilege Escalation
Adversaries may exploit software vulnerabilities in an attempt to elevate privileges.
Why these techniques?

Local memory corruption (buffer over-read) with low privileges directly enables exploitation for privilege escalation and arbitrary code execution on affected Qualcomm components.

Confidence: MEDIUM · MITRE ATT&CK Enterprise v18.1

NVD Description

Memory Corruption when retrieving output buffer with insufficient size validation.

Deeper analysisAI

CVE-2026-21371 is a memory corruption vulnerability stemming from insufficient size validation when retrieving an output buffer, classified under CWE-126 (Buffer Over-read). It affects components in Qualcomm products, as detailed in the vendor's security bulletin. The issue carries a CVSS v3.1 base score of 7.8 (AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H), indicating high severity with local attack vector, low attack complexity, and low privileges required.

A local attacker with low-level privileges can exploit this vulnerability without user interaction. Successful exploitation enables high-impact outcomes, including unauthorized access to sensitive data (confidentiality), modification of system resources (integrity), and denial of service or system crashes (availability), potentially leading to arbitrary code execution or privilege escalation within the affected Qualcomm components.

Qualcomm has published a security bulletin at https://docs.qualcomm.com/product/publicresources/securitybulletin/april-2026-bulletin.html, which provides details on the vulnerability and associated patches or mitigations for affected products. Security practitioners should consult this advisory for specific remediation steps.

Details

CWE(s)

Affected Products

qualcomm
aqt1000 firmware
all versions
qualcomm
cologne firmware
all versions
qualcomm
fastconnect 6200 firmware
all versions
qualcomm
fastconnect 6700 firmware
all versions
qualcomm
fastconnect 6800 firmware
all versions
qualcomm
fastconnect 6900 firmware
all versions
qualcomm
fastconnect 7800 firmware
all versions
qualcomm
qca0000 firmware
all versions
qualcomm
qca6391 firmware
all versions
qualcomm
qca6420 firmware
all versions
+42 more product configuration(s) — see NVD for full list

CVEs Like This One

CVE-2026-21374Same product: Qualcomm Aqt1000
CVE-2026-21376Same product: Qualcomm Aqt1000
CVE-2026-21373Same product: Qualcomm Aqt1000
CVE-2026-21378Same product: Qualcomm Aqt1000
CVE-2026-21375Same product: Qualcomm Cologne
CVE-2025-47390Same product: Qualcomm Cologne
CVE-2025-59600Same product: Qualcomm Fastconnect 6200
CVE-2026-21372Same product: Qualcomm Cologne
CVE-2025-47359Same product: Qualcomm Aqt1000
CVE-2025-47343Same product: Qualcomm Cologne

References