Medium · CVSS 4.9CVE-2023-6693

Qemu: virtio-net: stack buffer overflow in virtio_net_flush_tx()CVE-2023-6693

Answer in brief

CVE-2023-6693 records a Medium severity (CVSS 4.9) vulnerability in Qemu: virtio-net: stack buffer overflow in virtio_net_flush_tx(). The current sources do not mark it as known exploited. The current feed maps Red Hat/virt:av/qemu-kvm (generic). Check affected ranges and fixed versions before updating.

Analysis pending evidence review

HOL Guard separates source facts from reviewed analysis. See the methodology.

Published Jan 2, 2024Updated Nov 5, 2026Source checked Nov 5, 2026First seen by HOL Nov 5, 2026Material review Nov 5, 2026

Upstream Advisory

Key facts

Risk: Medium · CVSS 4.9
Exploitation: Not marked as known exploited
Affected software: 1 mapped package or product
Fix availability: Not reported

Why this deserves its current priority

CVSS is 4.9. The current sources do not mark it as known exploited. Treat this as a source-backed prioritization signal, not a statement about your environment.

Analysis status

Analysis pending evidence review

Factual feed record only; HOL analysis is not approved for indexing. Read the methodology.

Affected scope and exposure questions

The current feed maps Red Hat/virt:av/qemu-kvm (generic). Check affected ranges and fixed versions before updating.

Mapped affected packages and fixed versions
Package	Affected range	Fixed version
Red Hat/virt:av/qemu-kvmgeneric	*	Not reported

Recommended response

Check inventory. Check lockfiles and deployed manifests for Red Hat/virt:av/qemu-kvm.
Review the reported fix. Source-reported workaround: Mitigation for this issue is either not available or the currently available options do not meet the Red Hat Product Security criteria comprising ease of use and deployment, applicability to widespread installation base or stability.

Evidence timeline and material changes

Published upstream
Jan 2, 2024
Evidence: source:cvelist:source_dates:source-dates:record
Source modified
Nov 5, 2026
Evidence: source:cvelist:source_dates:source-dates:record
First seen by HOL
Nov 5, 2026

Sources and claim methodology

Upstream source 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.

Quoted source text, attributed separately from HOL analysis.

Package

Affected range

Fixed version

Red Hat/virt:av/qemu-kvmgeneric

Not reported

Recommended response

Check inventory. Check lockfiles and deployed manifests for Red Hat/virt:av/qemu-kvm.

Review the reported fix. Source-reported workaround: Mitigation for this issue is either not available or the currently available options do not meet the Red Hat Product Security criteria comprising ease of use and deployment, applicability to widespread installation base or stability.

Sources and claim methodology

Upstream source description

Quoted source text, attributed separately from HOL analysis.