CVE-2026-76151 Denial of service in qt
Remote attackers can crash applications using QtNetwork by sending oversized Cache-Control headers, causing a denial of service.
- Exploited in the wild
- Not known
- Login needed
- Not needed
- Attackable
- Over the internet
- Victim action needed
- Not needed
- Fix
- Available
What is CVE-2026-76151?
CVE-2026-76151 is a medium-severity denial of service vulnerability in qt, published on 16 Sep 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.
Official description
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.
Which versions are affected by CVE-2026-76151?
How do I fix CVE-2026-76151?
Apply the vendor's patch.
Upgrade, then put limits on request size, rate and nesting depth so one client cannot exhaust the service. More about Denial of service.
Is CVE-2026-76151 being exploited?
There is no known exploitation of CVE-2026-76151 in the wild and no public exploit code.
Sources
Also known as DEBIAN-CVE-2026-76151, ECHO-1632-1dd1-3803, GHSA-32mm-x94q-6h38, UBUNTU-CVE-2026-76151.