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CVE-2020-7039

22
FAUCET Score

CVE-2020-7039 describes a memory mismanagement vulnerability in libslirp 4.1.0 (specifically tcp_emu in tcp_subr.c), as utilized by QEMU 4.2.0, which can be triggered by IRC DCC commands. This flaw can lead to a heap-based buffer overflow or other out-of-bounds access, resulting in a Denial of Service or potential arbitrary code execution. Rated Medium (CVSS 5.6), it has a network attack vector and high attack complexity, with low impact on confidentiality, integrity, and availability. There is currently no evidence of active exploitation, public exploit code (Metasploit, Nuclei, ExploitDB), or significant community discussion surrounding this vulnerability.

Impacted Technologies

VendorProductVersion(s)CPE
4.1.0CPE matchmatch criteria
cpe:2.3:a:libslirp_project:libslirp:4.1.0:*:*:*:*:*:*:*
4.2.0CPE matchmatch criteria
cpe:2.3:a:qemu:qemu:4.2.0:*:*:*:*:*:*:*
8.0CPE matchmatch criteria
cpe:2.3:o:debian:debian_linux:8.0:*:*:*:*:*:*:*
9.0CPE matchmatch criteria
cpe:2.3:o:debian:debian_linux:9.0:*:*:*:*:*:*:*
15.1CPE matchmatch criteria
cpe:2.3:o:opensuse:leap:15.1:*:*:*:*:*:*:*

CVSS Data

CVSS version used by this source: 3.1

5.6MEDIUM

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

Attack Vector
NETWORK
Attack Complexity
HIGH
Privileges Required
NONE
User Interaction
NONE
Scope
UNCHANGED
Confidentiality Impact
LOW
Integrity Impact
LOW
Availability Impact
LOW
Exploitability Score
2.2
Impact Score
3.4
CvssVersion
3.1

Exploit Intelligence

EPSS Score
3.57%
Probability of exploitation in next 30 days
EPSS Percentile
88.1%
Percentile rank of EPSS score among Peer Group
As of 2026-07-27
Model: v2026.06.15
This CVE's current EPSS score of 0.0357 is in the 83rd percentile among its peer group of 19,956 CVEs.

Social Chatter

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

Media Mentions

No media coverage found for this CVE.

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

Remediation

Patch Available

Vendor Patches (25)

microsoftpatch availablevia msrc
Product: 16843-16820Fixed in: 4.2.0-13
microsoftpatch availablevia msrc
Product: cm1 qemu-kvm 4.2.0-13 on CBL Mariner 1.0Fixed in: 4.2.0-13
microsoftpatch availablevia msrc
Product: CBL Mariner 1.0 x64Fixed in: 4.2.0-13
microsoftpatch availablevia msrc
Product: CBL Mariner 1.0 ARMFixed in: 4.2.0-13
redhatpatch availablevia redhat_api
Product: Red Hat Enterprise Linux 6Fixed in: qemu-kvm-2:0.12.1.2-2.506.el6_10.6
View patch
redhatpatch availablevia redhat_api
Product: Red Hat Enterprise Linux 7Fixed in: qemu-kvm-ma-10:2.12.0-44.el7
View patch
redhatpatch availablevia redhat_api
Product: Red Hat Enterprise Linux 7.7 Extended Update SupportFixed in: qemu-kvm-10:1.5.3-167.el7_7.6
View patch
redhatpatch availablevia redhat_api
Product: Red Hat Enterprise Linux 7.7 Extended Update SupportFixed in: qemu-kvm-ma-10:2.12.0-33.el7_7.3
View patch
redhatpatch availablevia redhat_api
Product: Red Hat Enterprise Linux 7 ExtrasFixed in: slirp4netns-0:0.3.0-8.el7_7
View patch
redhatpatch availablevia redhat_api
Product: Red Hat Enterprise Linux 8Fixed in: container-tools:rhel8-8010120200116121758.53d07e52
View patch
redhatpatch availablevia redhat_api
Product: Red Hat Enterprise Linux 8Fixed in: virt-devel:rhel-8010020200304114113.c27ad7f8
View patch
redhatpatch availablevia redhat_api
Product: Red Hat Enterprise Linux 8Fixed in: virt:rhel-8010020200304114113.c27ad7f8
View patch
redhatpatch availablevia redhat_api
Product: Red Hat Enterprise Linux 8Fixed in: container-tools:1.0-8010020200206144344.c294d161
View patch
redhatpatch availablevia redhat_api
Product: Red Hat Enterprise Linux 8.0 Update Services for SAP SolutionsFixed in: virt:rhel-8000020200305185300.f8e95b4e
View patch
redhatpatch availablevia redhat_api
Product: Red Hat OpenShift Container Platform 4.3Fixed in: slirp4netns-0:0.4.2-3.git21fdece.el8
View patch
redhatpatch availablevia redhat_api
Product: Red Hat OpenStack Platform 10.0 (Newton)Fixed in: qemu-kvm-rhev-10:2.12.0-33.el7_7.10
View patch
redhatpatch availablevia redhat_api
Product: Red Hat OpenStack Platform 13.0 (Queens)Fixed in: qemu-kvm-rhev-10:2.12.0-44.el7
View patch
redhatpatch availablevia redhat_api
Product: Red Hat OpenStack Platform 13.0 (Queens)Fixed in: qemu-kvm-rhev-10:2.12.0-44.el7_8.1
View patch
redhatpatch availablevia redhat_api
Product: Red Hat OpenStack Platform 13.0 (Queens) for RHEL 7.6 EUSFixed in: qemu-kvm-rhev-10:2.12.0-18.el7_6.11
View patch
redhatpatch availablevia redhat_api
Product: Red Hat Virtualization Engine 4.2Fixed in: qemu-kvm-rhev-10:2.12.0-18.el7_6.11
View patch
redhatpatch availablevia redhat_api
Product: Advanced Virtualization for RHEL 8.1.1Fixed in: virt-devel:8.1-8010120200304224358.5db1954d
View patch
redhatpatch availablevia redhat_api
Product: Red Hat Enterprise Linux 7Fixed in: qemu-kvm-10:1.5.3-173.el7
View patch
redhatpatch availablevia redhat_api
Product: Advanced Virtualization for RHEL 8.1.1Fixed in: virt:8.1-8010120200304224358.5db1954d
View patch
redhatno patchvia redhat_api
Product: Red Hat Enterprise Linux 7Fixed in: qemu-kvm-rhev
redhatno patchvia redhat_api
Product: Red Hat Enterprise Linux 8 Advanced VirtualizationFixed in: qemu-kvm

Vendor Advisories (3)

microsoft2020-Nov/CVE-2020-7039

CVE-2020-7039

Nov 10, 2020
microsoft2020-Jan/CVE-2020-7039Moderate

tcp_emu in tcp_subr.c in libslirp 4.1.0 as used in QEMU 4.2.0 mismanages memory as demonstrated by IRC DCC commands in EMU_IRC. This can cause a heap-based buffer overflow or other out-of-bounds access which can lead to a DoS or potential execute arbitrary code.

Jan 14, 2020
redhatCVE-2020-7039Important

QEMU: slirp: OOB buffer access while emulating tcp protocols in tcp_emu()

Jan 7, 2020

References

lists.opensuse.org / opensuse-security-announce/2020-04/msg00007.html
Third Party Advisory
access.redhat.com / errata/RHSA-2020:0348
Third Party Advisory
access.redhat.com / errata/RHSA-2020:0775
Third Party Advisory
gitlab.freedesktop.org / slirp/libslirp/commit/2655fffed7a9e765bcb4701dd876e9dab975f289
PatchThird Party Advisory
gitlab.freedesktop.org / slirp/libslirp/commit/82ebe9c370a0e2970fb5695aa19aa5214a6a1c80
PatchThird Party Advisory
gitlab.freedesktop.org / slirp/libslirp/commit/ce131029d6d4a405cb7d3ac6716d03e58fb4a5d9
PatchThird Party Advisory
lists.debian.org / debian-lts-announce/2020/01/msg00022.html
Mailing ListThird Party Advisory
lists.debian.org / debian-lts-announce/2020/01/msg00036.html
Mailing ListThird Party Advisory
lists.debian.org / debian-lts-announce/2021/02/msg00012.html
Mailing ListThird Party Advisory
seclists.org / bugtraq/2020/Feb/0
Mailing ListThird Party Advisory
security.gentoo.org / glsa/202005-02
Third Party Advisory
usn.ubuntu.com / 4283-1
Third Party Advisory
debian.org / security/2020/dsa-4616
Third Party Advisory
openwall.com / lists/oss-security/2020/01/16/2
Mailing ListPatchThird Party Advisory