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CVE-2017-17563

25
FAUCET Score

CVE-2017-17563 is a high-severity vulnerability affecting Xen versions through 4.9.x, allowing a guest OS user to trigger a denial of service or gain host OS privileges due to an incorrect mask in shadow mode's reference-count overflow checking. The attack requires low privileges and high attack complexity, but can lead to complete compromise of confidentiality, integrity, and availability. There is no evidence of active exploitation, publicly available exploit code (Metasploit, Nuclei, ExploitDB), or significant community discussion or media coverage.

Impacted Technologies

VendorProductVersion(s)CPE
<= 4.9.1CPE matchmatch criteria
cpe:2.3:o:xen:xen:*:*:*:*:*:*:*:*

CVSS Data

CVSS version used by this source: 3.0

7.8HIGH

CVSS:3.0/AV:L/AC:H/PR:L/UI:N/S:C/C:H/I:H/A:H

Attack Vector
LOCAL
Attack Complexity
HIGH
Privileges Required
LOW
User Interaction
NONE
Scope
CHANGED
Confidentiality Impact
HIGH
Integrity Impact
HIGH
Availability Impact
HIGH
Exploitability Score
1.1
Impact Score
6.0
CvssVersion
3.0

Exploit Intelligence

EPSS Score
0.35%
Probability of exploitation in next 30 days
EPSS Percentile
27.7%
Percentile rank of EPSS score among Peer Group
As of 2026-07-27
Model: v2026.06.15
This CVE's current EPSS score of 0.0035 is in the 66th percentile among its peer group of 1,525 CVEs.

Social Chatter

The average CVE in this peer group has 0.0 Twitter, 0.1 Reddit, 0.1 Bluesky, 0.1 Mastodon, and 0.2 GitHub mentions.

Media Mentions

No media coverage found for this CVE.

The average CVE in this peer group has 0.4 InfoSec Media, 0.1 Vendor Blog, and 0.0 Security Researcher mentions.

Remediation

Vendor Advisories (1)

redhatCVE-2017-17563Important

xen: broken x86 shadow mode refcount overflow check (XSA-249)

Dec 12, 2017

References

lists.debian.org / debian-lts-announce/2018/01/msg00003.html
lists.debian.org / debian-lts-announce/2018/10/msg00009.html
security.gentoo.org / glsa/201801-14
support.citrix.com / article/CTX232096
debian.org / security/2018/dsa-4112
xenbits.xen.org / xsa/advisory-249.html
MitigationPatchVendor Advisory
openwall.com / lists/oss-security/2017/12/12/2
Mailing List
securityfocus.com / bid/102169
securitytracker.com / id/1040769