# CVE-2023-3255: Qemu: vnc: infinite loop in inflate_buffer() leads to denial of service

Status: published. Published: 2023-09-13. Updated: 2026-11-07.

A flaw was found in the QEMU built-in VNC server while processing ClientCutText messages. A wrong exit condition may lead to an infinite loop when inflating an attacker controlled zlib buffer in the `inflate_buffer` function. This could allow a remote authenticated client who is able to send a clipboard to the VNC server to trigger a denial of service.

## Remediation

No remediation reported in collected sources

## Affected products and versions

- Red Hat / Red Hat Enterprise Linux 8 (virt-devel:rhel): ≥ 8100020240314161907.e155f54d; < * (unaffected, rpm). Source: CNA: redhat
- Red Hat / Red Hat Enterprise Linux 8 (virt:rhel): ≥ 8100020240314161907.e155f54d; < * (unaffected, rpm). Source: CNA: redhat
- Red Hat / Red Hat Enterprise Linux 9 (qemu-kvm): ≥ 17:8.2.0-11.el9_4; < * (unaffected, rpm). Source: CNA: redhat
- Red Hat / Red Hat Enterprise Linux 6 (qemu-kvm): Version range not reported. Source: CNA: redhat
- Red Hat / Red Hat Enterprise Linux 7 (qemu-kvm): Version range not reported. Source: CNA: redhat
- Red Hat / Red Hat Enterprise Linux 7 (qemu-kvm-ma): Version range not reported. Source: CNA: redhat
- Red Hat / Red Hat Enterprise Linux 8 Advanced Virtualization (virt:av/qemu-kvm): Version range not reported. Source: CNA: redhat

## Severity and prioritization

- CVSS 3.1: 6.5 (medium); CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H; source: CNA: redhat

- CISA KEV: No listing in collected sources

- EPSS: 1.89% as of 2026-11-06; percentile 79.66%

- SSVC: exploitation none; automatable no; technical impact partial; source ADP: CISA-ADP

- Weaknesses: CWE-835

## Exploit evidence

No exploit evidence in collected sources. This is not proof of no exploitation.

## References

- https://access.redhat.com/errata/RHSA-2024:2135 (CNA: redhat; vendor-advisory, x_refsource_REDHAT)

- https://access.redhat.com/errata/RHSA-2024:2962 (CNA: redhat; vendor-advisory, x_refsource_REDHAT)

- https://access.redhat.com/security/cve/CVE-2023-3255 (CNA: redhat; vdb-entry, x_refsource_REDHAT)

- https://bugzilla.redhat.com/show_bug.cgi?id=2218486 (CNA: redhat; issue-tracking, x_refsource_REDHAT)

- https://access.redhat.com/errata/RHSA-2024:2135 (ADP: CVE; vendor-advisory, x_refsource_REDHAT, x_transferred)

- https://access.redhat.com/errata/RHSA-2024:2962 (ADP: CVE; vendor-advisory, x_refsource_REDHAT, x_transferred)

- https://access.redhat.com/security/cve/CVE-2023-3255 (ADP: CVE; vdb-entry, x_refsource_REDHAT, x_transferred)

- https://bugzilla.redhat.com/show_bug.cgi?id=2218486 (ADP: CVE; issue-tracking, x_refsource_REDHAT, x_transferred)

- https://security.netapp.com/advisory/ntap-20231020-0008/ (ADP: CVE; x_transferred)

## Provenance

- CNA: redhat: https://www.cve.org/CVERecord?id=CVE-2023-3255; retrieved 2026-11-07; source updated 2026-11-07

- FIRST EPSS: https://api.first.org/data/v1/epss?cve=CVE-2023-3255; retrieved 2026-11-07; source updated Not reported

Revision: 9bb3e844da80848a9b50279201fc940a1df4a76ec2f91f401265930046a13c70

Canonical: https://y2.dev/cve/CVE-2023-3255

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