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01 Record

CVE-2015-8555

Xen 4.6.x, 4.5.x, 4.4.x, 4.3.x, and earlier do not initialize x86 FPU stack and XMM registers when XSAVE/XRSTOR are not used to manage guest extended register state, which allows local guest domains

UnratedPUBLISHEDCNA: mitre
CNA base scoreUnratedNo CNA CVSS vector

02 Description

Xen 4.6.x, 4.5.x, 4.4.x, 4.3.x, and earlier do not initialize x86 FPU stack and XMM registers when XSAVE/XRSTOR are not used to manage guest extended register state, which allows local guest domains

03 Exploitation and scoring

Exploitation
Not assessed. CISA has not published an exploitation assessment for this record, and it is not in the KEV catalog. That is an absence of assessment, not a finding of no risk.
SSVC decision
Not assessed by CISA
EPSS probability
2.25% probability of exploitation activity in the next 30 days.
EPSS percentile
Equal to or higher than the score of 82.6% of scored records. A rank, not a probability.
NVD base score
8.6 (CVSS v3.x), scored by the NVD independently of the CNA.
NVD CVSS vector
CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:N/A:N
NVD analysis status
Modified. NVD last modified this record on 2026-06-17.
Red Hat severity
Low. Red Hat's rating for its own products, not a CVSS rating.

Exploit-prediction scores from FIRST. Independent scoring and analysis status from the NVD. Vendor severity from Red Hat. Exploitation assessment and catalog membership from CISA.

04 Metadata

Published
2016-04-13 15:00Z10 YR AGO
Last updated
2024-08-06 08:20Z2 YR AGO
Reserved
2015-12-14
Assigning CNA
mitre
Record state
PUBLISHED
Severity
Not rated by the issuing CNA
CNA CVSS vector
Not published by the issuing CNA
Weaknesses
  • CWE-200Exposure of Sensitive Information to an Unauthorized ActorClass
Data version
5.1
Document digest
e9ab47ed837b5459e84dcec7545fa5832e805103c58834160c3dd4733877a073

05 Affected products

VendorProductVersionsPlatforms
citrixxenserverNot specified—
redhatenterprise_linuxNot specified—
xenxenNot specified—

06 References

07 Fixed in

Debian 12

  • xen
    Fixed in 4.8.0~rc3-1

Source: Debian Security Tracker, the Debian security team. Received through OSV.dev. Reformatted by exploit.cc.

Debian 13

  • xen
    Fixed in 4.8.0~rc3-1

Source: Debian Security Tracker, the Debian security team. Received through OSV.dev. Reformatted by exploit.cc.

Debian 14

  • xen
    Fixed in 4.8.0~rc3-1

Source: Debian Security Tracker, the Debian security team. Received through OSV.dev. Reformatted by exploit.cc.

Ubuntu 14.04 LTS

  • xen
    Fixed in 4.4.2-0ubuntu0.14.04.4

Source: Ubuntu, Canonical Ltd. Licensed under CC BY-SA 4.0. Received through OSV.dev. Reformatted by exploit.cc.

A release or ecosystem missing from this list has no record here. It may be unaffected or not covered by the source. Source notices and licences.