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Fencer Vulns
medium 5.6

CVE-2020-7039 json

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.

published 2020-01-16 6 y ago modified 2026-06-17 4 mo ago also EUVD-2020-28173

cvss
5.6
version 3.1, NVD
cisa kev
Not listed
not in CISA's catalog
epss
3.6%
EPSS 3.6% chance of exploitation in 30 days, percentile 89%
public exploits
0
none known

Summary

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.

Patch / fix

  • qemu Debian 14, Debian 13, Debian 12 1:4.1-2
  • slirp Debian 14, Debian 13, Debian 12 1:1.0.17-10
  • libslirp Debian 14, Debian 13, Debian 12 4.1.0-2

debian advisories DEBIAN-CVE-2020-7039

  • qemu Ubuntu 16.04 LTS 1:2.5+dfsg-5ubuntu10.43
  • qemu Ubuntu 18.04 LTS 1:2.11+dfsg-1ubuntu7.23
  • slirp Ubuntu 16.04 LTS 1:1.0.17-8ubuntu16.04.1
  • slirp Ubuntu 18.04 LTS 1:1.0.17-8ubuntu18.04.1
  • qemu Ubuntu Pro 14.04 LTS 2.0.0+dfsg-2ubuntu1.47+esm4
  • slirp Ubuntu Pro 14.04 LTS 1:1.0.17-7+deb8u2build0.14.04.1+esm1

ubuntu advisories UBUNTU-CVE-2020-7039

Ubuntu security data © Canonical Ltd., from https://github.com/canonical/ubuntu-security-notices via OSV; changed: normalised to fixed package versions per release. CC BY-SA 4.0

  • qemu-kvm-rhev openstack 13 10:2.12.0-44.el7_8.1
  • qemu-img-rhev openstack 13 10:2.12.0-44.el7_8.1
  • qemu-kvm-tools-rhev openstack 13 10:2.12.0-44.el7_8.1
  • qemu-kvm-common-rhev openstack 13 10:2.12.0-44.el7_8.1
  • qemu-kvm-rhev rhev manager 4.2 10:2.12.0-18.el7_6.11
  • qemu-img-rhev rhev manager 4.2 10:2.12.0-18.el7_6.11
  • qemu-kvm-tools-rhev rhev manager 4.2 10:2.12.0-18.el7_6.11
  • qemu-kvm-common-rhev rhev manager 4.2 10:2.12.0-18.el7_6.11

red hat advisories RHSA-2020:1344RHSA-2020:2730RHSA-2020:2342RHSA-2020:1360RHSA-2020:1261RHSA-2020:1358

  • kvm SLE Point of Sale 11 SP3 1.4.2-53.38.1
  • qemu SLES for SAP 12 SP3, SLES 12 SP3-LTSS, SLES 12 SP3-BCL +4 more 2.9.1-6.44.1
  • qemu SLES for SAP 12 SP2, SLES 12 SP2-LTSS, SLES 12 SP2-BCL +1 more 2.6.2-41.59.1
  • qemu SLES for SAP 15, SLES 15-LTSS, SLE High Performance Computing 15-LTSS +1 more 2.11.2-9.36.1
  • qemu SLES for SAP 12 SP4, SLES 12 SP4 2.11.2-5.26.1
  • qemu SLES for SAP 12 SP5, SLES 12 SP5 3.1.1.1-3.9.1
  • qemu SLE Module for Server Applications 15 SP1, SLE Module for Basesystem 15 SP1 3.1.1.1-9.14.1
  • kvm SLES 11 SP4-LTSS 1.4.2-60.31.1

suse advisories SUSE-SU-2021:14706-1SUSE-SU-2020:14396-1SUSE-SU-2020:1538-1SUSE-SU-2020:1526-1SUSE-SU-2020:1523-1SUSE-SU-2020:1514-1

  • qemu openSUSE Tumbleweed 6.1.0-32.1
  • qemu openSUSE Leap 15.1 3.1.1.1-lp151.7.12.1
  • qemu-linux-user openSUSE Leap 15.1 3.1.1.1-lp151.7.12.1

opensuse advisories openSUSE-SU-2024:11287-1openSUSE-SU-2020:0468-1

  • runc AlmaLinux 8 1.0.0-56.rc5.dev.git2abd837.module_el8.3.0+2044+12421f43
  • runc AlmaLinux 8 1.0.0-56.rc5.dev.git2abd837.module_el8.4.0+2496+12421f43
  • runc AlmaLinux 8 1.0.0-56.rc5.dev.git2abd837.module_el8.5.0+119+9a9ec082
  • skopeo AlmaLinux 8 1:0.1.32-6.git1715c90.module_el8.4.0+2496+12421f43
  • skopeo AlmaLinux 8 1:0.1.32-6.git1715c90.module_el8.5.0+119+9a9ec082
  • skopeo AlmaLinux 8 1:0.1.32-6.git1715c90.module_el8.4.0+2478+12421f43
  • oci-umount AlmaLinux 8 2:2.3.4-2.git87f9237.module_el8.5.0+119+9a9ec082
  • oci-umount AlmaLinux 8 2:2.3.4-2.git87f9237.module_el8.4.0+2496+12421f43

almalinux advisories ALSA-2020:1360ALSA-2020:1358ALSA-2020:0348

  • runc Rocky Linux 8 1.0.0-56.rc5.dev.git2abd837.module+el8.5.0+681+c9a1951f
  • runc Rocky Linux 8 1.0.0-56.rc5.dev.git2abd837.module+el8.4.0+557+48ba8b2f
  • skopeo Rocky Linux 8 1:0.1.32-6.git1715c90.module+el8.5.0+681+c9a1951f
  • skopeo Rocky Linux 8 1:0.1.32-6.git1715c90.module+el8.4.0+557+48ba8b2f
  • oci-umount Rocky Linux 8 2:2.3.4-2.git87f9237.module+el8.4.0+557+48ba8b2f
  • fuse-overlayfs Rocky Linux 8 0.3-5.module+el8.5.0+681+c9a1951f
  • fuse-overlayfs Rocky Linux 8 0.3-5.module+el8.4.0+557+48ba8b2f
  • oci-systemd-hook Rocky Linux 8 1:0.1.15-2.git2d0b8a3.module+el8.4.0+557+48ba8b2f

rocky linux advisories RLSA-2020:1360RLSA-2020:1358RLSA-2020:0348

Vendor advisories

What the vendors themselves say about their products: affected, fixed or not affected, and what to do.

red hat product security vex CVE-2020-7039 updated cvss 5.6

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

  • Red Hat Enterprise Linux 5 kvm
    affected: workaround, no fix planned “Out of support scope”
  • Red Hat Enterprise Linux 7 qemu-kvm-rhev Red Hat Enterprise Linux 8 Advanced Virtualization qemu-img, qemu-kvm, qemu-kiwi, qemu-kvm-core, qemu-kvm-tests, qemu-kvm-common, +9 more
    affected: workaround, no fix available
  • Red Hat Advanced Virtualization CodeReady Builder for RHEL 8.1.1 hivex 1.3.15-7.module+el8.1.1+5309+6d656f05, libnbd 1.0.3-1.module+el8.1.1+5659+15cacc69, netcf 0.2.8-12.module+el8.1.1+5309+6d656f05, libvirt 5.6.0-10.module+el8.1.1+5309+6d656f05, seabios 1.12.0-5.module+el8.1.1+5309+6d656f05, libiscsi 1.18.0-8.module+el8.1.1+5309+6d656f05, +44 more Red Hat Advanced Virtualization for RHEL 8.1.1 hivex 1.3.15-7.module+el8.1.1+5309+6d656f05, libnbd 1.0.3-1.module+el8.1.1+5659+15cacc69, netcf 0.2.8-12.module+el8.1.1+5309+6d656f05, nbdkit 1.12.5-2.module+el8.1.1+5309+6d656f05, libvirt 5.6.0-10.module+el8.1.1+5309+6d656f05, seabios 1.12.0-5.module+el8.1.1+5309+6d656f05, +97 more
    fixed: vendor fix RHSA-2020:1261
  • Red Hat CodeReady Linux Builder (v. 8) hivex 1.3.15-7.module+el8.1.0+4066+0f1aadab, netcf 0.2.8-12.module+el8.1.0+4066+0f1aadab, seabios 1.11.1-4.module+el8.1.0+4066+0f1aadab, libiscsi 1.18.0-8.module+el8.1.0+4066+0f1aadab, libvirt 4.5.0-35.3.module+el8.1.0+5931+8897e7e1, netcf-libs 0.2.8-12.module+el8.1.0+4066+0f1aadab, +34 more
    fixed: vendor fix RHSA-2020:1358
  • Red Hat Enterprise Linux 7 Extras slirp4netns 0.3.0-8.el7_7
    fixed: vendor fix RHSA-2020:0889
  • Red Hat Enterprise Linux AppStream (v. 8) udica 0.2.1-2.module+el8.1.1+4975+482d6f5d, conmon 2.0.6-1.module+el8.1.1+5259+bcdd613a, hivex 1.3.15-7.module+el8.1.0+4066+0f1aadab, nbdkit 1.4.2-5.module+el8.1.0+4066+0f1aadab, netcf 0.2.8-12.module+el8.1.0+4066+0f1aadab, podman 1.6.4-2.module+el8.1.1+5363+bf8ff1af, +113 more
    fixed: vendor fix RHSA-2020:1358
  • Red Hat Enterprise Linux AppStream E4S (v. 8.0) hivex 1.3.15-7.module+el8.0.0+4084+cceb9f44, nbdkit 1.4.2-5.module+el8.0.0+4084+cceb9f44, netcf 0.2.8-11.module+el8.0.0+4084+cceb9f44, seabios 1.11.1-4.module+el8.0.0+4084+cceb9f44, libiscsi 1.18.0-7.module+el8.0.0+4084+cceb9f44, libssh2 1.8.0-8.module+el8.0.0+4084+cceb9f44.1, +82 more
    fixed: vendor fix RHSA-2020:1344
  • Red Hat Enterprise Linux Client (v. 7) qemu-img 1.5.3-173.el7, qemu-kvm 1.5.3-173.el7, qemu-kvm-tools 1.5.3-173.el7, qemu-kvm-common 1.5.3-173.el7 Red Hat Enterprise Linux ComputeNode Optional (v. 7) qemu-img 1.5.3-173.el7, qemu-kvm 1.5.3-173.el7, qemu-kvm-tools 1.5.3-173.el7, qemu-kvm-common 1.5.3-173.el7
    fixed: vendor fix RHSA-2020:1116
show 13 more
  • Red Hat Enterprise Linux ComputeNode Optional EUS (v. 7.7) qemu-img 1.5.3-167.el7_7.6, qemu-kvm 1.5.3-167.el7_7.6, qemu-kvm-tools 1.5.3-167.el7_7.6, qemu-kvm-common 1.5.3-167.el7_7.6
    fixed: vendor fix RHSA-2020:1351
  • Red Hat Enterprise Linux Desktop (v. 6) qemu-img 0.12.1.2-2.506.el6_10.6, qemu-kvm 0.12.1.2-2.506.el6_10.6, qemu-kvm-tools 0.12.1.2-2.506.el6_10.6, qemu-guest-agent 0.12.1.2-2.506.el6_10.6 Red Hat Enterprise Linux HPC Node (v. 6) qemu-img 0.12.1.2-2.506.el6_10.6, qemu-kvm 0.12.1.2-2.506.el6_10.6, qemu-kvm-tools 0.12.1.2-2.506.el6_10.6, qemu-guest-agent 0.12.1.2-2.506.el6_10.6 Red Hat Enterprise Linux Server (v. 6) qemu-img 0.12.1.2-2.506.el6_10.6, qemu-kvm 0.12.1.2-2.506.el6_10.6, qemu-kvm-tools 0.12.1.2-2.506.el6_10.6, qemu-guest-agent 0.12.1.2-2.506.el6_10.6
    fixed: vendor fix RHSA-2020:0775
  • Red Hat Enterprise Linux Server (v. 7) qemu-img 1.5.3-173.el7, qemu-kvm 1.5.3-173.el7, qemu-img-ma 2.12.0-44.el7, qemu-kvm-ma 2.12.0-44.el7, qemu-kvm-tools 1.5.3-173.el7, qemu-kvm-common 1.5.3-173.el7, +2 more
    fixed: vendor fix RHSA-2020:1116
  • Red Hat Enterprise Linux Server EUS (v. 7.7) qemu-img 1.5.3-167.el7_7.6, qemu-kvm 1.5.3-167.el7_7.6, qemu-img-ma 2.12.0-33.el7_7.3, qemu-kvm-ma 2.12.0-33.el7_7.3, qemu-kvm-tools 1.5.3-167.el7_7.6, qemu-kvm-common 1.5.3-167.el7_7.6, +2 more
    fixed: vendor fix RHSA-2020:1351
  • Red Hat Enterprise Linux Server Optional (v. 7) qemu-kvm-ma 2.12.0-44.el7, qemu-kvm-tools-ma 2.12.0-44.el7, qemu-kvm-common-ma 2.12.0-44.el7
    fixed: vendor fix RHSA-2020:1150
  • Red Hat Enterprise Linux Server Optional EUS (v. 7.7) qemu-kvm-ma 2.12.0-33.el7_7.3, qemu-kvm-tools-ma 2.12.0-33.el7_7.3, qemu-kvm-common-ma 2.12.0-33.el7_7.3
    fixed: vendor fix RHSA-2020:1352
  • Red Hat Enterprise Linux Workstation (v. 6) qemu-img 0.12.1.2-2.506.el6_10.6, qemu-kvm 0.12.1.2-2.506.el6_10.6, qemu-kvm-tools 0.12.1.2-2.506.el6_10.6, qemu-guest-agent 0.12.1.2-2.506.el6_10.6
    fixed: vendor fix RHSA-2020:0775
  • Red Hat Enterprise Linux Workstation (v. 7) qemu-img 1.5.3-173.el7, qemu-kvm 1.5.3-173.el7, qemu-kvm-tools 1.5.3-173.el7, qemu-kvm-common 1.5.3-173.el7
    fixed: vendor fix RHSA-2020:1116
  • Red Hat OpenShift Container Platform 4.3 slirp4netns 0.4.2-3.git21fdece.el8
    fixed: vendor fix RHBA-2020:0390
  • Red Hat OpenStack Platform 10.0 qemu-img-rhev 2.12.0-33.el7_7.10, qemu-kvm-rhev 2.12.0-33.el7_7.10, qemu-kvm-tools-rhev 2.12.0-33.el7_7.10, qemu-kvm-common-rhev 2.12.0-33.el7_7.10
    fixed: vendor fix RHSA-2020:1300
  • Red Hat OpenStack Platform 13.0 qemu-img-rhev 2.12.0-44.el7, qemu-kvm-rhev 2.12.0-44.el7, qemu-img-rhev 2.12.0-44.el7_8.1, qemu-kvm-rhev 2.12.0-44.el7_8.1, qemu-kvm-tools-rhev 2.12.0-44.el7, qemu-kvm-common-rhev 2.12.0-44.el7, +2 more Red Hat OpenStack Platform 13.0 for RHEL 7.6 EUS Server qemu-img-rhev 2.12.0-18.el7_6.11, qemu-kvm-rhev 2.12.0-18.el7_6.11, qemu-kvm-tools-rhev 2.12.0-18.el7_6.11, qemu-kvm-common-rhev 2.12.0-18.el7_6.11
    fixed: vendor fix RHSA-2020:2730
  • Red Hat RHV-M 4.2 qemu-img-rhev 2.12.0-18.el7_6.11, qemu-kvm-rhev 2.12.0-18.el7_6.11, qemu-kvm-tools-rhev 2.12.0-18.el7_6.11, qemu-kvm-common-rhev 2.12.0-18.el7_6.11
    fixed: vendor fix RHSA-2020:2342
  • Red Hat Enterprise Linux 5 xen Red Hat OpenShift Container Platform 4.3 skopeo 0.1.40-3.rhaos.el8, rhosp-release 16.0.0-1.el8ost, skopeo-tests 0.1.40-3.rhaos.el8, containers-common 0.1.40-3.rhaos.el8, ignition 0.34.0-2.rhaos4.3.git92f874c.el8, cri-o 1.16.2-13.dev.rhaos4.3.gita83f883.el7, +23 more
    not affected: vulnerable code not present

Red Hat CSAF VEX © Red Hat, Inc., from https://security.access.redhat.com/data/csaf/v2/vex/; changed: reduced to product statuses and remediations. CC BY 4.0 · csaf

Exploit prediction

3.57% chance of exploitation in the next 30 days, higher than 89% of all scored CVEs (FIRST EPSS, 2026-11-08).

CVSS scores

assigned by version score vector
NVD 3.1 5.6 CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:L/I:L/A:L
NVD 2.0 6.8 AV:N/AC:M/Au:N/C:P/I:P/A:P

Classification

Weakness

References

Sources

Fencer Vulns keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.