CVE-2022-42332 Use after free in xen

What is CVE-2022-42332?

CVE-2022-42332 is a high-severity use after free vulnerability in Debian Debian Linux, published on 21 Mar 2023. It can only be exploited from the same machine or local network, with no action from the victim.

Official description

x86 shadow plus log-dirty mode use-after-free In environments where host assisted address translation is necessary but Hardware Assisted Paging (HAP) is unavailable, Xen will run guests in so called shadow mode. Shadow mode maintains a pool of memory used for both shadow page tables as well as auxiliary data structures. To migrate or snapshot guests, Xen additionally runs them in so called log-dirty mode. The data structures needed by the log-dirty tracking are part of aformentioned auxiliary data. In order to keep error handling efforts within reasonable bounds, for operations which may require memory allocations shadow mode logic ensures up front that enough memory is available for the worst case requirements. Unfortunately, while page table memory is properly accounted for on the code path requiring the potential establishing of new shadows, demands by the log-dirty infrastructure were not taken into consideration. As a result, just established shadow page tables could be freed again immediately, while other code is still accessing them on the assumption that they would remain allocated.

Weakness: CWE-416

Which versions are affected by CVE-2022-42332?

It affects 3 products.

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

How do I fix CVE-2022-42332?

Apply the vendor's patch.

Upgrade to the fixed version. These bugs are found with fuzzing and sanitisers and avoided by memory-safe languages. More about Use after free.

Is CVE-2022-42332 being exploited?

There is no known exploitation of CVE-2022-42332 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 ALPINE-CVE-2022-42332, DEBIAN-CVE-2022-42332, GHSA-jg93-x3r7-r8pf, UBUNTU-CVE-2022-42332.