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Fencer Vulns
medium 5.5

CVE-2023-46835 json

x86/AMD: mismatch in IOMMU quarantine page table levels

published 2024-01-05 2 y ago modified 2026-06-17 4 mo ago also EUVD-2023-51001

cvss
5.5
version 3.1, CNA
cisa kev
Not listed
not in CISA's catalog
epss
0.3%
EPSS 0.3% chance of exploitation in 30 days, percentile 21%
public exploits
0
none known

Summary

The current setup of the quarantine page tables assumes that the quarantine domain (dom_io) has been initialized with an address width of DEFAULT_DOMAIN_ADDRESS_WIDTH (48) and hence 4 page table levels.

However dom_io being a PV domain gets the AMD-Vi IOMMU page tables levels based on the maximum (hot pluggable) RAM address, and hence on systems with no RAM above the 512GB mark only 3 page-table levels are configured in the IOMMU.

On systems without RAM above the 512GB boundary amd_iommu_quarantine_init() will setup page tables for the scratch page with 4 levels, while the IOMMU will be configured to use 3 levels only, resulting in the last page table directory (PDE) effectively becoming a page table entry (PTE), and hence a device in quarantine mode gaining write access to the page destined to be a PDE.

Due to this page table level mismatch, the sink page the device gets read/write access to is no longer cleared between device assignment, possibly leading to data leaks.

Patch / fix

  • xen Debian 12 4.17.2+76-ge1f9cb16e2-1~deb12u1
  • xen Debian 14, Debian 13 4.17.2+76-ge1f9cb16e2-1

debian advisories DEBIAN-CVE-2023-46835

  • xen SLE Module for Server Applications 15 SP5, SLE Module for Basesystem 15 SP5, SLE Micro 5.5 +1 more 4.17.3_02-150500.3.18.1
  • xen SLES for SAP 12 SP5, SLES 12 SP5, SLE Software Development Kit 12 SP5 4.12.4_42-3.100.1
  • xen SLE Module for Server Applications 15 SP4, SLE Module for Basesystem 15 SP4, SLE Micro 5.4 +4 more 4.16.5_08-150400.4.40.1
  • xen SLE Module for Server Applications 15 SP5, SLE Module for Basesystem 15 SP5, SLE Micro 5.5 +1 more 4.17.2_08-150500.3.15.1
  • xen SLES for SAP 15 SP3, SLES 15 SP3-LTSS, SLE Micro 5.2 +4 more 4.14.6_08-150300.3.60.1
  • xen SLES for SAP 15 SP1, SLES 15 SP1-LTSS, SLE High Performance Computing 15 SP1-LTSS 4.12.4_42-150100.3.98.1
  • xen SLES for SAP 15 SP2, SLES 15 SP2-LTSS, SLE High Performance Computing 15 SP2-LTSS 4.13.5_08-150200.3.83.1

suse advisories SUSE-SU-2023:4945-1SUSE-SU-2023:4486-1SUSE-SU-2023:4485-1SUSE-SU-2023:4484-1SUSE-SU-2023:4476-1SUSE-SU-2023:4475-1

  • xen openSUSE Tumbleweed 4.18.0_02-1.1

opensuse advisories openSUSE-SU-2024:13442-1

  • xen Alpine 3.15 4.15.5-r3
  • xen Alpine 3.17, Alpine 3.16 4.16.5-r4
  • xen Alpine 3.24, Alpine 3.23, Alpine 3.22 +4 more 4.17.2-r4

alpine advisories ALPINE-CVE-2023-46835

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

CISA SSVC

Exploitation
none
Automatable
no
Technical impact
partial
Assessed
2 y ago

Exploit prediction

0.28% chance of exploitation in the next 30 days, higher than 21% of all scored CVEs (FIRST EPSS, 2026-11-08).

CVSS scores

assigned by version score vector
CISA ADP 3.1 5.5 CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:N
NVD 3.1 5.5 CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:N
CNA 3.1 5.5 CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:N

Affected products

  • Xen Xen

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.