Skip to content
Fencer Intel
medium 6.0

CVE-2020-29484 json

An issue was discovered in Xen through 4.14.x.

published 5y ago modified 4mo ago also EUVD-2020-21852

cvss
6.0
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. When a Xenstore watch fires, the xenstore client that registered the watch will receive a Xenstore message containing the path of the modified Xenstore entry that triggered the watch, and the tag that was specified when registering the watch. Any communication with xenstored is done via Xenstore messages, consisting of a message header and the payload. The payload length is limited to 4096 bytes. Any request to xenstored resulting in a response with a payload longer than 4096 bytes will result in an error. When registering a watch, the payload length limit applies to the combined length of the watched path and the specified tag. Because watches for a specific path are also triggered for all nodes below that path, the payload of a watch event message can be longer than the payload needed to register the watch. A malicious guest that registers a watch using a very large tag (i.e., with a registration operation payload length close to the 4096 byte limit) can cause the generation of watch events with a payload length larger than 4096 bytes, by writing to Xenstore entries below the watched path. This will result in an error condition in xenstored. This error can result in a NULL pointer dereference, leading to a crash of xenstored. A malicious guest administrator can cause xenstored to crash, leading to a denial of service. Following a xenstored crash, domains may continue to run, but management operations will be impossible. Only C xenstored is affected, oxenstored is not affected.

Patch / fix

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

debian advisories DEBIAN-CVE-2020-29484

  • 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-2020-29484

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

Is CVE-2020-29484 in your stack? Fencer shows which of your repositories are affected as soon as an advisory lands, and opens the fix as a pull request.

Check with Fencer

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-2020-29484 updated cvss 4.0

xen: Xenstore: guests can crash xenstored via watchs (XSA-324)

  • 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, 2026-11-09).

CVSS scores

assigned by version score vector
NVD 3.1 6.0 CVSS:3.1/AV:L/AC:L/PR:H/UI:N/S:C/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 Intel 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.