What is CVE-2018-10839?

CVE-2018-10839 is a medium-severity vulnerability in Qemu, classified under Stack-based Buffer Overflow. CVSS score: 6.5/10. Published 2018-10-16.

How severe is CVE-2018-10839?

Medium severity. CVSS v3 base score is 6.5 out of 10.

Is CVE-2018-10839 known to be exploited?

1 public proof-of-concept repositories are indexed. Not currently listed in the CISA KEV catalog.

Buffer overflow in Qemu

CVE-2018-10839

Qemu emulator <= 3.0.0 built with the NE2000 NIC emulation support is vulnerable to an integer overflow, which could lead to buffer overflow issue. It could occur when receiving packets over the network. A user inside guest could use this flaw to crash the Qemu process resulting in DoS.

Vulnerability class: Buffer Overflow

Published 2018-10-16 · last modified 2026-06-17.

CVSS v3 metric

CVSS v3 base score 6.5 (Medium). Vector: CVSS:3.0/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:L/A:H.

EPSS exploit prediction

EPSS: 0.031 (87.2th percentile), scored 2026-09-30.

Low probability of exploitation in the next 30 days, but still tracked. 87th percentile — 87.2% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.

EPSS over last 30 days · oldest: 0.032 · newest: 0.031 · change: -0.001

Affected products

Qemu
The Qemu Project Qemu-Kvm — versions <= 3.0.0
Canonical Ubuntu Linux — versions 14.04, 16.04, 18.04
Debian Linux — versions 8.0, 9.0

Weakness classification (CWE)

Public proof-of-concept exploits

msftsecurityteam/contrived_

References

bugzilla.redhat.com/show_bug.cgi (Third Party Advisory, Issue Tracking)
www.debian.org/security/2018/dsa-4338 (vendor-advisory, Vendor Advisory)
usn.ubuntu.com/3826-1/ (vendor-advisory, Patch, Vendor Advisory)
www.openwall.com/lists/oss-security/2018/10/08/1 (mailing-list, Mailing List, Third Party Advisory)
lists.debian.org/debian-lts-announce/2018/11/msg00038.html (mailing-list, Third Party Advisory)
lists.gnu.org/archive/html/qemu-devel/2018-09/msg03273.html (mailing-list, Exploit, Mailing List, Third Party Advisory)
access.redhat.com/errata/RHSA-2019:2892 (vendor-advisory)

Frequently asked questions

What is CVE-2018-10839?: CVE-2018-10839 is a medium-severity vulnerability in Qemu, classified under Stack-based Buffer Overflow. CVSS score: 6.5/10. Published 2018-10-16.
How severe is CVE-2018-10839?: Medium severity. CVSS v3 base score is 6.5 out of 10.
Is CVE-2018-10839 known to be exploited?: 1 public proof-of-concept repositories are indexed. Not currently listed in the CISA KEV catalog.