Skip to content
Fencer Vulns
medium 6.2

CVE-2020-29571 json

An issue was discovered in Xen through 4.14.x.

published 2020-12-15 5 y ago modified 2026-06-17 4 mo ago also EUVD-2020-21933

cvss
6.2
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 issue was discovered in Xen through 4.14.x. A bounds check common to most operation time functions specific to FIFO event channels depends on the CPU observing consistent state. While the producer side uses appropriately ordered writes, the consumer side isn't protected against re-ordered reads, and may hence end up de-referencing a NULL pointer. Malicious or buggy guest kernels can mount a Denial of Service (DoS) attack affecting the entire system. Only Arm systems may be vulnerable. Whether a system is vulnerable depends on the specific CPU. x86 systems are not vulnerable.

Patch / fix

  • xen Debian 14, Debian 13, Debian 12 4.14.0+88-g1d1d1f5391-1

debian advisories DEBIAN-CVE-2020-29571

  • xen SLES for SAP 12 SP3, SLES 12 SP3-LTSS, SLES 12 SP3-BCL +4 more 4.9.4_16-3.80.1
  • xen SLES for SAP 15, SLE High Performance Computing 15-LTSS, SLE High Performance Computing 15-ESPOS 4.10.4_24-3.53.1
  • xen SLE Module for Server Applications 15 SP2, SLE Module for Basesystem 15 SP2 4.13.2_06-3.22.1
  • xen SLES for SAP 12 SP4, SLES 12 SP4-LTSS, OpenStack Cloud Crowbar 9 +1 more 4.11.4_16-2.48.1
  • xen SLES for SAP 12 SP2, SLES 12 SP2-LTSS, SLES 12 SP2-BCL +1 more 4.7.6_14-43.73.1
  • xen SLE Module for Server Applications 15 SP1, SLE Module for Basesystem 15 SP1 4.12.4_06-3.40.1
  • xen SLES for SAP 12 SP5, SLES 12 SP5, SLE Software Development Kit 12 SP5 4.12.4_06-3.36.1
  • xen SLES 11 SP4-LTSS 4.4.4_48-61.61.1

suse advisories SUSE-SU-2020:3945-1SUSE-SU-2020:3916-1SUSE-SU-2020:3915-1SUSE-SU-2020:3914-1SUSE-SU-2020:3913-1SUSE-SU-2020:3881-1

  • xen openSUSE Tumbleweed 4.15.1_01-1.2
  • xen openSUSE Leap 15.2 4.13.2_06-lp152.2.21.1
  • xen openSUSE Leap 15.1 4.12.4_06-lp151.2.36.1

opensuse advisories openSUSE-SU-2024:11520-1openSUSE-SU-2020:2331-1openSUSE-SU-2020:2313-1

  • xen Alpine 3.12, Alpine 3.11 4.13.2-r3
  • xen Alpine 3.24, Alpine 3.23, Alpine 3.22 +9 more 4.14.1-r0

alpine advisories ALPINE-CVE-2020-29571

Alpine secdb © Alpine Linux, from https://secdb.alpinelinux.org via OSV; changed: normalised to fixed package versions per release. CC BY-SA 4.0

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-2020-29571 updated cvss 5.1

xen: FIFO event channels control structure ordering

  • Red Hat All currently supported Red Hat products
    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

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

CVSS scores

assigned by version score vector
NVD 3.1 6.2 CVSS:3.1/AV:L/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
NVD 2.0 4.9 AV:L/AC:L/Au:N/C:N/I:N/A:C

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.