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CVE-2017-1000256

25
FAUCET Score

CVE-2017-1000256 describes a critical vulnerability in libvirt versions 2.3.0 and later, affecting Debian and Red Hat distributions, where a default misconfiguration of "verify-peer=no" for QEMU leads to a failure in validating SSL/TLS certificates. This high-severity vulnerability (CVSS 8.1) allows unauthenticated attackers to compromise confidentiality, integrity, and availability over the network with high impact, despite high attack complexity. There is no evidence of active exploitation, publicly available exploit code, or significant community discussion surrounding this CVE.

Impacted Technologies

VendorProductVersion(s)CPE
>= 2.3.0, < 3.9.0CPE matchmatch criteria
cpe:2.3:a:redhat:libvirt:*:*:*:*:*:*:*:*
9.0CPE matchmatch criteria
cpe:2.3:o:debian:debian_linux:9.0:*:*:*:*:*:*:*

CVSS Data

CVSS version used by this source: 3.1

8.1HIGH

CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H

Attack Vector
NETWORK
Attack Complexity
HIGH
Privileges Required
NONE
User Interaction
NONE
Scope
UNCHANGED
Confidentiality Impact
HIGH
Integrity Impact
HIGH
Availability Impact
HIGH
Exploitability Score
2.2
Impact Score
5.9
CvssVersion
3.1

Exploit Intelligence

EPSS Score
1.70%
Probability of exploitation in next 30 days
EPSS Percentile
74.8%
Percentile rank of EPSS score among Peer Group
As of 2026-07-25
Model: v2026.06.15
This CVE's current EPSS score of 0.0170 is in the 32nd percentile among its peer group of 8,914 CVEs.

Social Chatter

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

Media Mentions

No media coverage found for this CVE.

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

Remediation

Patch Available

Vendor Patches (9)

microsoftpatch availablevia msrc
Product: CBL Mariner 1.0 x64Fixed in: 6.1.0-1
microsoftpatch availablevia msrc
Product: 16889-16820Fixed in: 6.1.0-1
microsoftpatch availablevia msrc
Product: cm1 libvirt 6.1.0-1 on CBL Mariner 1.0Fixed in: 6.1.0-1
microsoftpatch availablevia msrc
Product: CBL Mariner 1.0 ARMFixed in: 6.1.0-1
redhatvendor investigatingvia nvd_reference
View patch
redhatend of lifevia redhat_api
Product: Red Hat Enterprise Linux 7Fixed in: libvirt
redhatend of lifevia redhat_api
Product: Red Hat Enterprise Virtualization 3Fixed in: mingw-virt-viewer
redhatend of lifevia redhat_api
Product: Red Hat Enterprise Linux 6Fixed in: libvirt
redhatend of lifevia redhat_api
Product: Red Hat Enterprise Linux 5Fixed in: libvirt

Vendor Advisories (3)

microsoft2020-Sep/CVE-2017-1000256

CVE-2017-1000256

Sep 8, 2020
redhatCVE-2017-1000256Low

libvirt: TLS certificate verification disabled for clients

Oct 16, 2017
microsoft2017-Oct/CVE-2017-1000256Important

libvirt version 2.3.0 and later is vulnerable to a bad default configuration of "verify-peer=no" passed to QEMU by libvirt resulting in a failure to validate SSL/TLS certificates by default.

Oct 10, 2017

References

access.redhat.com / security/cve/CVE-2017-1000256
Issue TrackingVendor Advisory
mail-archive.com / debian-bugs-dist%40lists.debian.org/msg1556251.html
redhat.com / archives/libvirt-announce/2017-October/msg00001.html
Issue TrackingVendor Advisory
debian.org / security/2017/dsa-4003
Third Party Advisory