A vulnerability was found in QEMU (Virtualization Software) (affected version not known). It has been classified as critical. Affected is some unknown functionality of the file hw/rdma/rdma_backend.c. The manipulation of the argument num_sge with an unknown input leads to a out-of-bounds vulnerability. CWE is classifying the issue as CWE-125. The product reads data past the end, or before the beginning, of the intended buffer. This is going to have an impact on confidentiality, integrity, and availability. CVE summarizes:

hw/rdma/rdma_backend.c in QEMU allows guest OS users to trigger out-of-bounds access via a PvrdmaSqWqe ring element with a large num_sge value.

The bug was discovered 12/18/2018. The weakness was released 12/20/2018 (oss-sec). The advisory is shared for download at openwall.com. This vulnerability is traded as CVE-2018-20124 since 12/13/2018. The exploitability is told to be easy. The attack needs to be approached locally. The exploitation doesn't require any form of authentication. There are known technical details, but no exploit is available. The current price for an exploit might be approx. USD $0-$5k (estimation calculated on 06/20/2023).

The vulnerability was handled as a non-public zero-day exploit for at least 2 days. During that time the estimated underground price was around $0-$5k. The commercial vulnerability scanner Qualys is able to test this issue with plugin 157908 (Oracle Enterprise Linux Security Update for qemu (ELSA-2019-4518)).

There is no information about possible countermeasures known. It may be suggested to replace the affected object with an alternative product.

Entries connected to this vulnerability are available at 127948, 128257, 128258 and 128259.

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Type

• Virtualization Software

Name

• QEMU

License

• open-source

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