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Fencer Intel
medium 4.9

CVE-2015-2756 json

QEMU, as used in Xen 3.3.x through 4.5.x, does not properly restrict access to PCI command registers, which might allow local HVM guest use…

published 2015-04-01 11 y ago modified 2026-06-17 4 mo ago also EUVD-2015-2846

cvss
4.9
version 2.0, NVD
cisa kev
Not listed
not in CISA's catalog
epss
0.4%
EPSS 0.4% chance of exploitation in 30 days, percentile 39%
public exploits
0
none known

Summary

QEMU, as used in Xen 3.3.x through 4.5.x, does not properly restrict access to PCI command registers, which might allow local HVM guest users to cause a denial of service (non-maskable interrupt and host crash) by disabling the (1) memory or (2) I/O decoding for a PCI Express device and then accessing the device, which triggers an Unsupported Request (UR) response.

Patch / fix

  • xen Debian 14, Debian 13, Debian 12 4.2.0~rc2-1
  • qemu Debian 14, Debian 13, Debian 12 1:2.3+dfsg-3

debian advisories DEBIAN-CVE-2015-2756

  • xen Ubuntu 14.04 LTS 4.4.1-0ubuntu0.14.04.5
  • qemu Ubuntu 14.04 LTS 2.0.0+dfsg-2ubuntu1.11

ubuntu advisories UBUNTU-CVE-2015-2756

Ubuntu security data © Canonical Ltd., from https://github.com/canonical/ubuntu-security-notices via OSV; changed: normalised to fixed package versions per release. CC BY-SA 4.0

  • xen SLES for SAP 12, SLES 12, SLED 12 +1 more 4.4.2_02-15.1

suse advisories SUSE-SU-2015:0701-1

Vendor advisories

What the vendors themselves say about their products: affected, fixed or not affected, and what to do.

red hat product security vex CVE-2015-2756 updated cvss 4.3

xen: unmediated PCI command register access in qemu (xsa126)

  • Red Hat Enterprise Linux 5 xen
    affected: no fix available

Red Hat CSAF VEX © Red Hat, Inc., from https://security.access.redhat.com/data/csaf/v2/vex/; changed: reduced to product statuses and remediations. CC BY 4.0 · csaf

Exploit prediction

0.45% chance of exploitation in the next 30 days, higher than 39% of all scored CVEs (FIRST EPSS, 2026-11-09).

CVSS scores

assigned by version score vector
NVD 2.0 4.9 AV:L/AC:L/Au:N/C:N/I:N/A:C

Classification

Weakness
  • CWE-264 Permissions, Privileges, and Access Controls

References

Sources

Fencer Intel keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.