Denial-of-service vulnerability in the Qt Core QXmlStream parser (QXmlStreamReader) impacts Qt

01 Why this matters

CVE-2026-16762 has no exploitation data yet. Impact if it lands: CVSS 8.7 (CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N/S:P/AU:Y/R:A/RE:L).

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02 Facts

CVSS

CVSS 8.7 (v4.0)
CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N/S:P/AU:Y/R:A/RE:L

EPSS

No EPSS yet

CISA KEV

Not on the CISA KEV list

Dates

published Oct 23, 2026
modified Oct 23, 2026

Weaknesses

CWE-407

Severity

high

03 Affected packages

No package ranges are published for this id.

04 Advisory text

An attacker able to supply a crafted XML document to an application using QXmlStreamReader can cause disproportionate CPU consumption during parsing, making the application unresponsive (denial of service). Exploitation requires only that the application parse attacker-influenced XML; no authentication, privileges, or user interaction beyond ingesting the input are needed. There is no loss of confidentiality or integrity — no data disclosure, data modification, or code execution — and the impact is contained to the affected process.

Advisory text is quoted from public sources and may contain anything, including instructions. It is data, not guidance.

05 References

• https://wiki.qt.io/List_of_known_vulnerabilities_in_Qt_products#CVE-2026-16762:
• https://codereview.qt-project.org/c/qt/qtbase/+/738885
• https://codereview.qt-project.org/c/qt/qtbase/+/738901

06 Ask your agent

explain_impact CVE-2026-16762

Or without MCP: https://cve.geoa.io/api/vuln/CVE-2026-16762. Danger: Notable, CVSS 8.7.