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Fencer Intel
critical 9.8

CVE-2019-18425 json

An issue was discovered in Xen through 4.12.x allowing 32-bit PV guest OS users to gain guest OS privileges by installing and using descrip…

published 7y ago modified 4mo ago also EUVD-2019-8194

cvss
9.8
version 3.1, NVD
cisa kev
Not listed
not in CISA's catalog
epss
2.5%
EPSS 2.5% chance of exploitation in 30 days, percentile 85%
public exploits
0
none known

Summary

An issue was discovered in Xen through 4.12.x allowing 32-bit PV guest OS users to gain guest OS privileges by installing and using descriptors. There is missing descriptor table limit checking in x86 PV emulation. When emulating certain PV guest operations, descriptor table accesses are performed by the emulating code. Such accesses should respect the guest specified limits, unless otherwise guaranteed to fail in such a case. Without this, emulation of 32-bit guest user mode calls through call gates would allow guest user mode to install and then use descriptors of their choice, as long as the guest kernel did not itself install an LDT. (Most OSes don't install any LDT by default). 32-bit PV guest user mode can elevate its privileges to that of the guest kernel. Xen versions from at least 3.2 onwards are affected. Only 32-bit PV guest user mode can leverage this vulnerability. HVM, PVH, as well as 64-bit PV guests cannot leverage this vulnerability. Arm systems are unaffected.

Patch / fix

  • xen Debian 14, Debian 13, Debian 12 4.11.3+24-g14b62ab3e5-1

debian advisories DEBIAN-CVE-2019-18425

  • xen SLE Point of Sale 11 SP3 4.2.5_22-45.36.1
  • xen SLES for SAP 12 SP2, SLES 12 SP2-LTSS, SLES 12 SP2-BCL +1 more 4.7.6_06-43.59.1
  • xen SLES for SAP 12 SP3, SLES 12 SP3-LTSS, SLES 12 SP3-BCL +4 more 4.9.4_06-3.59.1
  • xen SLES for SAP 12 SP4, SLES 12 SP4, SLED 12 SP4 +1 more 4.11.2_04-2.17.1
  • xen SLE Module for Server Applications 15 SP1, SLE Module for Basesystem 15 SP1 4.12.1_04-3.6.1
  • xen SLE Module for Server Applications 15, SLE Module for Basesystem 15 4.10.4_06-3.25.1
  • xen SLES 11 SP4-LTSS 4.4.4_42-61.52.1
  • xen SLES for SAP 12 SP1, SLES 12 SP1-LTSS 4.5.5_28-22.64.1

suse advisories SUSE-SU-2020:14448-1SUSE-SU-2020:14444-1SUSE-SU-2020:0388-1SUSE-SU-2020:0334-1SUSE-SU-2019:3297-1SUSE-SU-2019:2962-1

  • xen openSUSE Leap 15.0 4.10.4_06-lp150.2.25.1

opensuse advisories openSUSE-SU-2019:2506-1

  • xen Alpine 3.10 4.12.1-r1
  • xen Alpine 3.24, Alpine 3.23, Alpine 3.22 +11 more 4.13.0-r0
  • xen Alpine 3.8 4.10.4-r1
  • xen Alpine 3.9 4.11.2-r1

alpine advisories ALPINE-CVE-2019-18425

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-2019-18425 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.

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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-2019-18425 updated cvss 8.0

xen: missing descriptor table limit checking in x86 PV emulation leading to privilege escalation

  • Red Hat Enterprise Linux 5 kernel-xen
    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

2.55% chance of exploitation in the next 30 days, higher than 85% of all scored CVEs (FIRST EPSS, 2026-11-09).

CVSS scores

assigned by version score vector
NVD 3.1 9.8 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
NVD 2.0 9.3 AV:N/AC:M/Au:N/C:C/I:C/A:C

Classification

Weakness
  • CWE-269 Improper Privilege Management

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.