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CVE-2021-45464

28
FAUCET Score

CVE-2021-45464 describes an out-of-bounds write vulnerability in kvmtool, specifically within the virtio/balloon.c and virtio/pci.c components, affecting kvmtool up to commit 39181fc. This critical flaw allows a guest operating system user to execute arbitrary code on the host machine. With a CVSS score of 8.8 (High), it presents a significant risk due to its low attack complexity and the potential for complete compromise of confidentiality, integrity, and availability. While there is no evidence of active exploitation, public exploit code, or KEV listing, the vulnerability has garnered some community discussion and media coverage, indicating awareness within the cybersecurity community.

Impacted Technologies

VendorProductVersion(s)CPE
Range not provided by sourceCPE matchmatch criteria
cpe:2.3:a:kvmtool_project:kvmtool:-:*:*:*:*:*:*:*

CVSS Data

CVSS version used by this source: 3.1

8.8HIGH

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

Attack Vector
LOCAL
Attack Complexity
LOW
Privileges Required
LOW
User Interaction
NONE
Scope
CHANGED
Confidentiality Impact
HIGH
Integrity Impact
HIGH
Availability Impact
HIGH
Exploitability Score
2.0
Impact Score
6.0
CvssVersion
3.1

Exploit Intelligence

EPSS Score
0.38%
Probability of exploitation in next 30 days
EPSS Percentile
30.7%
Percentile rank of EPSS score among Peer Group
As of 2026-07-27
Model: v2026.06.15
This CVE's current EPSS score of 0.0038 is in the 70th percentile among its peer group of 17,070 CVEs.

Social Chatter

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

Media Mentions

The average CVE in this peer group has 0.3 InfoSec Media, 0.0 Vendor Blog, and 0.0 Security Researcher mentions.

Remediation

Patch Available

Vendor Patches (4)

ubuntupatch availablevia ubuntu_usn
Product: kvmtool (bionic)Fixed in: 0.20170904-1ubuntu0.18.04.1~esm1
ubuntupatch availablevia ubuntu_usn
Product: kvmtool (focal)Fixed in: 0.20170904-1ubuntu0.20.04.1~esm1
ubuntupatch availablevia ubuntu_usn
Product: kvmtool (jammy)Fixed in: 0.20170904-1.1ubuntu0.1~esm2
ubuntupatch availablevia ubuntu_usn
Product: kvmtool (xenial)Fixed in: 0.20151104-1ubuntu0.1~esm1

Vendor Advisories (1)

ubuntuUSN-8172-1

kvmtool vulnerabilities

Apr 13, 2026

References

cdn.discordapp.com / attachments/921419715170164776/921882173517230100/exploit.c
Broken Link
git.kernel.org / pub/scm/linux/kernel/git/will/kvmtool.git/commit
Patch
git.kernel.org / pub/scm/linux/kernel/git/will/kvmtool.git/log
Patch
kalmarunionen.dk / writeups/2021/hxp-2021/lkvm
ExploitThird Party Advisory