CVE-2026-95509
Description
A flaw was found in Qt for MCUs. An incorrect buffer size calculation occurs during String.arg() formatting when handling Latin-1 encoded characters, leading to an out-of-bounds read. A remote attacker could supply specially crafted string input to trigger this flaw, resulting in an application crash leading to a Denial of Service (DoS) or limited information disclosure.
Statement
An out-of-bounds read vulnerability was found in Qt for MCUs during String.arg() formatting of Latin-1 encoded characters due to an incorrect buffer size calculation. When an application processes specially crafted input containing Latin-1 strings, a remote attacker can trigger a read operation past allocated buffer boundaries. This flaw leads to an immediate application crash, causing a denial of service, or the potential exposure of adjacent process memory. Default Red Hat process isolation and container boundary controls limit the technical impact strictly to the unprivileged executing process.
Mitigation
Sanitize and validate untrusted input to reject unexpected Latin-1 character sequences before passing strings to String.arg() formatting functions. Where possible, restrict network access to services exposing vulnerable string formatting routines.
Common Vulnerability Scoring System (CVSS) Score Details
Info alert:Important note
CVSS scores for open source components depend on vendor-specific factors (e.g. version or build chain). Therefore, Red Hat's score and impact rating can be different from NVD and other vendors. Red Hat remains the authoritative CVE Naming Authority (CNA) source for its products and services (see Red Hat classifications).
CVSS v3 Score Breakdown
| Red Hat | NVD | cve.org | |
|---|---|---|---|
| Base Score | 8.2 | N/A | N/A |
| Attack Vector | Network | N/A | N/A |
| Attack Complexity | Low | N/A | N/A |
| Privileges Required | None | N/A | N/A |
| User Interaction | None | N/A | N/A |
| Scope | Unchanged | N/A | N/A |
| Confidentiality | Low | N/A | N/A |
| Integrity Impact | None | N/A | N/A |
| Availability Impact | High | N/A | N/A |
Vector
Red Hat: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:H
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