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Fencer Vulns
low 3.2

CVE-2020-14394 json

An infinite loop flaw was found in the USB xHCI controller emulation of QEMU while computing the length of the Transfer Request Block (TRB)…

published 2022-08-17 4 y ago modified 2026-06-17 4 mo ago also EUVD-2020-6533

cvss
3.2
version 3.1, NVD
cisa kev
Not listed
not in CISA's catalog
epss
0.4%
EPSS 0.4% chance of exploitation in 30 days, percentile 33%
public exploits
0
none known

Summary

An infinite loop flaw was found in the USB xHCI controller emulation of QEMU while computing the length of the Transfer Request Block (TRB) Ring. This flaw allows a privileged guest user to hang the QEMU process on the host, resulting in a denial of service.

Patch / fix

  • qemu Debian 14, Debian 13, Debian 12 1:7.1+dfsg-1

debian advisories DEBIAN-CVE-2020-14394

  • qemu Ubuntu 20.04 LTS 1:4.2-3ubuntu6.28
  • qemu Ubuntu 22.04 LTS 1:6.2+dfsg-2ubuntu6.16
  • qemu Ubuntu Pro 14.04 LTS 2.0.0+dfsg-2ubuntu1.47+esm6
  • qemu Ubuntu Pro 16.04 LTS 1:2.5+dfsg-5ubuntu10.51+esm4
  • qemu Ubuntu Pro 18.04 LTS 1:2.11+dfsg-1ubuntu7.42+esm5

ubuntu advisories UBUNTU-CVE-2020-14394

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 SLE Module for Server Applications 15 SP4, SLE Module for Basesystem 15 SP4, SLE Micro 5.4 +3 more 6.2.0-150400.37.14.2
  • qemu-testsuite openSUSE Leap 15.4 6.2.0-150400.37.14.1
  • qemu-linux-user openSUSE Leap 15.4 6.2.0-150400.37.14.1
  • qemu SLES for SAP 15 SP3, SLES 15 SP3-LTSS, SLE Real Time 15 SP3 +7 more 5.2.0-150300.121.2
  • qemu SLES for SAP 12 SP5, SLES 12 SP5 3.1.1.1-66.1

suse advisories SUSE-SU-2023:0879-2SUSE-SU-2023:0879-1SUSE-SU-2023:0840-1SUSE-SU-2023:0761-1

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-2020-14394 updated cvss 3.2

QEMU: infinite loop in xhci_ring_chain_length() in hw/usb/hcd-xhci.c

  • Red Hat Enterprise Linux 5 kvm, xen Red Hat Enterprise Linux 6 qemu-img, qemu-kvm, qemu-kvm-tools, qemu-guest-agent, qemu-guest-agent-win32 Red Hat Enterprise Linux 7 qemu-img, qemu-kvm, libcacard, qemu-img-ma, qemu-kvm-ma, qemu-kvm-rhev, +6 more
    affected: no fix planned “Out of support scope”
  • Red Hat Enterprise Linux 8 qemu-img, qemu-kvm, qemu-kvm-core, qemu-kvm-tests, qemu-kvm-common, qemu-guest-agent, +8 more Red Hat Enterprise Linux 8 Advanced Virtualization qemu-img, qemu-kvm, qemu-kiwi, qemu-kvm-core, qemu-kvm-tests, qemu-kvm-common, +9 more Red Hat Enterprise Linux 9 qemu-img, qemu-kvm, qemu-kvm-core, qemu-kvm-tools, qemu-pr-helper, qemu-kvm-common, +16 more
    affected: no fix available “Fix deferred”
  • Red Hat OpenStack Platform 10 (Newton) qemu-img-rhev, qemu-kvm-rhev, qemu-kvm-tools-rhev, qemu-kvm-common-rhev Red Hat OpenStack Platform 13 (Queens) qemu-img-rhev, qemu-kvm-rhev, qemu-kvm-tools-rhev, qemu-kvm-common-rhev
    affected: no fix planned “Out of support scope”

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

0.39% chance of exploitation in the next 30 days, higher than 33% of all scored CVEs (FIRST EPSS, 2026-11-08).

Exploits and checks

  • gitlab.com https://gitlab.com/qemu-project/qemu/-/issues/646 referenced PoC, tagged "exploit" by a source, unverified
  • bugzilla.redhat.com https://bugzilla.redhat.com/show_bug.cgi?id=1908004 referenced PoC, tagged "exploit" by a source, unverified

CVSS scores

assigned by version score vector
NVD 3.1 3.2 CVSS:3.1/AV:L/AC:L/PR:H/UI:N/S:C/C:N/I:N/A:L

Affected products

  • n/a QEMU

Classification

Weakness
  • CWE-835 Loop with Unreachable Exit Condition

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.