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CVE-2016-4439

23
FAUCET Score

CVE-2016-4439 describes an out-of-bounds write vulnerability in the QEMU 53C9X Fast SCSI Controller (FSC) support, specifically within the esp_reg_write function in hw/scsi/esp.c. This flaw, caused by improper command buffer length checking, affects various QEMU installations across Canonical and Debian Linux distributions. With a CVSS score of 6.7 (Medium), this vulnerability allows local guest OS administrators to trigger a denial of service (QEMU process crash) or potentially execute arbitrary code on the QEMU host. The attack requires high privileges (PR:H) but has low attack complexity (AC:L) and no user interaction (UI:N). There is no evidence of active exploitation, nor are there publicly available exploit modules in Metasploit, Nuclei, or ExploitDB. The vulnerability has received minimal community discussion and media coverage, indicating a low level of public awareness or active threat.

Impacted Technologies

VendorProductVersion(s)CPE
12.04CPE matchmatch criteria
cpe:2.3:o:canonical:ubuntu_linux:12.04:*:*:*:lts:*:*:*
14.04CPE matchmatch criteria
cpe:2.3:o:canonical:ubuntu_linux:14.04:*:*:*:lts:*:*:*
16.04CPE matchmatch criteria
cpe:2.3:o:canonical:ubuntu_linux:16.04:*:*:*:lts:*:*:*
<= 2.6.0CPE matchmatch criteria
cpe:2.3:a:qemu:qemu:*:*:*:*:*:*:*:*
8.0CPE matchmatch criteria
cpe:2.3:o:debian:debian_linux:8.0:*:*:*:*:*:*:*

CVSS Data

CVSS version used by this source: 3.1

6.7MEDIUM

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

Attack Vector
LOCAL
Attack Complexity
LOW
Privileges Required
HIGH
User Interaction
NONE
Scope
UNCHANGED
Confidentiality Impact
HIGH
Integrity Impact
HIGH
Availability Impact
HIGH
Exploitability Score
0.8
Impact Score
5.9
CvssVersion
3.1

Exploit Intelligence

EPSS Score
0.46%
Probability of exploitation in next 30 days
EPSS Percentile
37.4%
Percentile rank of EPSS score among Peer Group
As of 2026-07-27
Model: v2026.06.15
This CVE's current EPSS score of 0.0046 is in the 88th percentile among its peer group of 3,720 CVEs.

Social Chatter

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

Vendor Advisories (1)

redhatCVE-2016-4439Moderate

Qemu: scsi: esp: OOB write while writing to 's->cmdbuf' in esp_reg_write

May 19, 2016

References

bugzilla.redhat.com / show_bug.cgi
Issue TrackingThird Party AdvisoryVDB Entry
lists.debian.org / debian-lts-announce/2018/11/msg00038.html
Mailing ListThird Party Advisory
lists.gnu.org / archive/html/qemu-devel/2016-05/msg03273.html
Mailing ListPatchThird Party Advisory
security.gentoo.org / glsa/201609-01
Third Party Advisory
openwall.com / lists/oss-security/2016/05/19/3
Mailing ListPatchThird Party Advisory
securityfocus.com / bid/90760
Third Party AdvisoryVDB Entry
ubuntu.com / usn/USN-3047-1
Third Party Advisory
ubuntu.com / usn/USN-3047-2
Third Party Advisory