What is CVE-2026-0665?

CVE-2026-0665 is a medium-severity vulnerability in Red Hat Enterprise Linux 10, classified under Out-of-bounds Write. CVSS score: 6.5/10. Published 2026-02-18.

How severe is CVE-2026-0665?

Medium severity. CVSS v3 base score is 6.5 out of 10.

Buffer overflow in Red Hat Enterprise Linux 10

CVE-2026-0665

An off-by-one error was found in QEMU's KVM Xen guest support. A malicious guest could use this flaw to trigger out-of-bounds heap accesses in the QEMU process via the emulated Xen physdev hypercall interface, leading to a denial of service or potential memory corruption.

Vulnerability class: Buffer Overflow

Published 2026-02-18 · last modified 2026-06-17.

CVSS v3 metric

CVSS v3 base score 6.5 (Medium). Vector: CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:C/C:N/I:N/A:H.

EPSS exploit prediction

EPSS: 0.002 (3.8th percentile), scored 2026-10-01.

Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 4th percentile — 3.8% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.

EPSS over last 30 days · oldest: 0.001 · newest: 0.002 · change: +0.000

Affected products

Weakness classification (CWE)

CWE-787 — Out-of-bounds Write

References

access.redhat.com/security/cve/CVE-2026-0665 (vdb-entry)
bugzilla.redhat.com/show_bug.cgi (issue-tracking)

Frequently asked questions

What is CVE-2026-0665?: CVE-2026-0665 is a medium-severity vulnerability in Red Hat Enterprise Linux 10, classified under Out-of-bounds Write. CVSS score: 6.5/10. Published 2026-02-18.
How severe is CVE-2026-0665?: Medium severity. CVSS v3 base score is 6.5 out of 10.