CVE-2020-7039

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.

Published: 2020-01-16 Last update: 2024-11-21 Assigner: [email protected] Source: [email protected]
NVD Status：Modified，CVE State: published
View at NVD, CVE.org, EUVD

CVE-2020-7039 is rated Moderate Risk (48.1/100): CVSS Medium severity, with medium exploitation likelihood (EPSS 0.83%). Review affected assets and schedule remediation.

Risk is dynamic; we continuously reassess and refresh what is shown on this page as upstream context changes.

Exploit prediction scoring system (EPSS) score for CVE-2020-7039

EPSS lead: Daily EPSS estimates relative likelihood of exploitation; percentile ranks this CVE among scored vulnerabilities (higher = more severe relative rank).

# Date Old EPSS score New EPSS score Delta (New - Old)
1 2025-12-20 1.00% 0.83% -0.17%
2 2025-11-21 3.22% 1.00% -2.22%
3 2025-11-18 — 3.22% —

Full EPSS history (17 records total)

Common vulnerability scoring system (CVSS) metrics for CVE-2020-7039

CVSS metrics for this CVE.

Base score Version Severity Vector Exploitability Impact Score source
5.6 3.1 MEDIUM
CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:L/I:L/A:L Click to expand
Attack vector (AV:N)
Could be attacked over the internet or any normal routed network—not just someone sitting at the machine.
Attack complexity (AC:H)
Even with access, the exploit needs extra luck, timing, or a fussy environment to actually work.
Privileges required (PR:N)
No account or special rights needed—anonymous or random user is enough.
User interaction (UI:N)
Nobody has to click “OK” or open a trap file; it can work without a victim helping.
Scope (S:U)
Damage stays in the same “trust bubble” as the broken component—no big spill into unrelated systems.
Confidentiality (C:L)
Some sensitive info could get out, but not a total data dump.
Integrity (I:L)
Attackers could change some data, but it’s limited—not everything goes.
Availability (A:L)
Might cause slowdowns, glitches, or partial disruption—not a full brick.
 2.2 3.4 [email protected]
6.8 2.0 MEDIUM
AV:N/AC:M/Au:N/C:P/I:P/A:P Click to expand
Access vector (AV:N)
Can be exploited remotely over network reachability.
Access complexity (AC:M)
Exploitation needs some favorable conditions, but not exceptional ones.
Authentication (AU:N)
No authentication is required.
Confidentiality impact (C:P)
Partial confidentiality impact.
Integrity impact (I:P)
Partial integrity impact.
Availability impact (A:P)
Partial availability impact.
 8.6 6.4 [email protected]

Weakness enumeration for CVE-2020-7039

OS Trackers for CVE-2020-7039

vendor priority summary link
debian not yet assigned CVE-2020-7039 not yet assigned priority: Debian including 3 source packages (libslirp, qemu, slirp), 15 status rows across 5 suites (bookworm, bullseye, forky, sid, trixie): resolved 15. https://security-tracker.debian.org/tracker/CVE-2020-7039
gentoo normal CVE-2020-7039: 1 GLSA(s) (202005-02), 1 atom(s) (app-emulation/qemu); latest impact normal. https://bugs.gentoo.org/buglist.cgi?quicksearch=CVE-2020-7039
redhat high — https://access.redhat.com/security/cve/CVE-2020-7039
suse high CVE-2020-7039 severity important: SUSE including 958 source package names (amazon/suse-sles-15-sp1-chost-byos-v20210304-hvm-ssd-x86_64, amazon/suse-sles-15-sp1-chost-byos-v20220127-hvm-ssd-x86_64, …), 1298 product×package rows across 60 product lines (HPE Helion OpenStack 8, Image SLES12-SP5-EC2-ECS-On-Demand, … (60 product lines)): Fixed 1043, Known Affected 231, Known Not Affected 24. https://www.suse.com/security/cve/CVE-2020-7039/
ubuntu medium CVE-2020-7039 medium priority: Ubuntu including 4 source packages (libslirp, qemu, qemu-kvm, slirp), 64 status rows across 16 suites (bionic, disco, eoan, focal, groovy, hirsute, impish, jammy, kinetic, lunar, mantic, noble, oracular, trusty, upstream, xenial): not-affected 30, DNE 20, released 9, ignored 3, needed 1, needs-triage 1. https://ubuntu.com/security/CVE-2020-7039

Affected software / configurations for CVE-2020-7039

Vendor Product Version Raw CPE
libslirp_project libslirp 4.1.0 cpe:2.3:a:libslirp_project:libslirp:4.1.0:*:*:*:*:*:*:*
qemu qemu 4.2.0 cpe:2.3:a:qemu:qemu:4.2.0:*:*:*:*:*:*:*
debian debian_linux 8.0 cpe:2.3:o:debian:debian_linux:8.0:*:*:*:*:*:*:*
debian debian_linux 9.0 cpe:2.3:o:debian:debian_linux:9.0:*:*:*:*:*:*:*
opensuse leap 15.1 cpe:2.3:o:opensuse:leap:15.1:*:*:*:*:*:*:*

References for CVE-2020-7039

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