CVE-2021-28699 Memory corruption in xen

Medium 5.5 Published 27 Aug 2021 Updated 3 Aug 2024

A buffer overflow in the Xen hypervisor's grant table interface allows a malicious guest to corrupt memory, potentially leading to code execution or privilege escalation.

Exploited in the wild: Not known
Login needed: Any signed-in user
Attackable: Local or same network only
Victim action needed: Not needed
Fix: Available

What is CVE-2021-28699?

CVE-2021-28699 is a medium-severity memory corruption vulnerability in Debian Debian Linux, published on 27 Aug 2021. It can only be exploited from the same machine or local network, with no action from the victim.

Official description

inadequate grant-v2 status frames array bounds check The v2 grant table interface separates grant attributes from grant status. That is, when operating in this mode, a guest has two tables. As a result, guests also need to be able to retrieve the addresses that the new status tracking table can be accessed through. For 32-bit guests on x86, translation of requests has to occur because the interface structure layouts commonly differ between 32- and 64-bit. The translation of the request to obtain the frame numbers of the grant status table involves translating the resulting array of frame numbers. Since the space used to carry out the translation is limited, the translation layer tells the core function the capacity of the array within translation space. Unfortunately the core function then only enforces array bounds to be below 8 times the specified value, and would write past the available space if enough frame numbers needed storing.

Which versions are affected by CVE-2021-28699?

It affects 3 products.

Products include Debian Debian Linux, Fedoraproject Fedora, Xen Xen.

How do I fix CVE-2021-28699?

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-2021-28699 being exploited?

There is no known exploitation of CVE-2021-28699 in the wild and no public exploit code.

All Debian Debian Linux vulnerabilities

Sources

Also known as ALPINE-CVE-2021-28699, DEBIAN-CVE-2021-28699, GHSA-gp69-2mv4-2f25, UBUNTU-CVE-2021-28699.