CVE-2026-76151

What it is

Out-of-bounds read (buffer over-read) in the HTTP Cache-Control response header parsing in the QtNetwork module in Qt Group Qt 6.0.0 through 6.8.8, and 6.9.0 through 6.11.1, allows remote attackers to cause a denial of service (application crash) via an excessively large Cache-Control header value returned by an untrusted or compromised HTTP server to an application using QNetworkAccessManager. Only the client side of the connection is affected and 32-bit builds are not affected; the out-of-bounds access is read-only, with no information disclosure and no code execution.

At a glance

Exploitability

Can be exploited over the network without logging in. High risk of service disruption.

Exploit odds

0.7% chance of exploitation in the next 30 days (EPSS).

Fix

No patch or advisory is linked yet. Look at mitigations or restrict exposure.

Timeline

1. 2026-09-16 10:16 UTC PublishedDisclosed publicly on CVE.org and NVD
2. 2026-09-18 19:21 UTC Last updatedMost recent change to the record

Details

Published

2026-09-16 10:16 UTC

Last modified

2026-09-18 19:21 UTC

Exploit probability

0.7% · EPSS, next 30 days

Weakness

CWE-125 · Out-of-bounds read

Record status

Awaiting Analysis

Attack profile CVSS 4.0 · 4.6

Attack vector

Network

Complexity

Low

Attack requirements

Present

Privileges needed

None

User interaction

None

Confidentiality

None

Integrity

None

Availability

High