CVE-2023-6816 Xorg-x11-server: heap buffer overflow in devicefocusevent and procxiquerypointer

What is CVE-2023-6816?

CVE-2023-6816 is a critical memory corruption vulnerability in Debian Debian Linux, published on 18 Jan 2024. An attacker can exploit it over the internet without logging in, with no action from the victim.

Official description

A flaw was found in X.Org server. Both DeviceFocusEvent and the XIQueryPointer reply contain a bit for each logical button currently down. Buttons can be arbitrarily mapped to any value up to 255, but the X.Org Server was only allocating space for the device's particular number of buttons, leading to a heap overflow if a bigger value was used.

Weakness: CWE-787

Which versions are affected by CVE-2023-6816?

It affects 7 products.

Products include Debian Debian Linux, Fedoraproject Fedora, Redhat Enterprise Linux Desktop, Redhat Enterprise Linux Server, Redhat Enterprise Linux Workstation, X.org X Server and 1 more.

How do I fix CVE-2023-6816?

Apply the vendor's patch.

Upgrade to the fixed version. Memory-safe languages, compiler hardening and fuzzing prevent most new cases. More about Memory corruption.

Is CVE-2023-6816 being exploited?

There is no known exploitation of CVE-2023-6816 in the wild and no public exploit code.

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All Debian Debian Linux vulnerabilities

Sources

• CVE record
• NVD
• OSV
• GitHub advisory
• How this page is made

Also known as AZL-33353, AZL-44742, BELL-CVE-2023-6816, CLSA-2025-1763124505, DEBIAN-CVE-2023-6816, GHSA-pcjv-393q-rqf2 and 1 more.