CVE-2023-6693: A stack based buffer overflow was found in the virtio-net device of QEMU. This issue occurs when flushing TX in the virtio_net_flush_tx function if gu...

Description

A stack based buffer overflow was found in the virtio-net device of QEMU. This issue occurs when flushing TX in the virtio_net_flush_tx function if guest features VIRTIO_NET_F_HASH_REPORT, VIRTIO_F_VERSION_1 and VIRTIO_NET_F_MRG_RXBUF are enabled. This could allow a malicious user to overwrite local variables allocated on the stack. Specifically, the `out_sg` variable could be used to read a part of process memory and send it to the wire, causing an information leak.

Metrics

CVSS 3.1

5.3/10

CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:L/I:L/A:L

EPSS Probability

0.33%

24.7th percentile

Probability of exploitation in the next 30 days. Learn more

Weakness Enumeration

Affected Software

Vendor	Product	Versions
Qemu	Qemu	< 8.2.1
Redhat	Enterprise Linux	8.0
Redhat	Enterprise Linux	9.0
Fedoraproject	Fedora	39

References

Timeline

Published: Jan 2, 2024
Last Modified: Jun 17, 2026
Status: Modified

Frequently Asked Questions

What is CVE-2023-6693?

A stack based buffer overflow was found in the virtio-net device of QEMU. This issue occurs when flushing TX in the virtio_net_flush_tx function if guest features VIRTIO_NET_F_HASH_REPORT, VIRTIO_F_VERSION_1 and VIRTIO_NET_F_MRG_RXBUF are enabled. This could allow a malicious user to overwrite local variables allocated on the stack. Specifically, the `out_sg` variable could be used to read a part of process memory and send it to the wire, causing an information leak.

How severe is CVE-2023-6693?

CVE-2023-6693 has a CVSS score of 5.3/10 (MEDIUM severity). The EPSS model estimates a 0.33% probability of exploitation in the next 30 days.

How do I fix CVE-2023-6693?

Check the vendor references and advisories linked above for patched versions and mitigation guidance. You can also run a Strix scan to test if your systems are affected.