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CVE-2021-28708 Affecting xen package, versions <4.15.1-r2

Severity

 Recommended
0.0
high
0
10

Snyk's Security Team recommends NVD's CVSS assessment

    Threat Intelligence

    EPSS
    0.06% (29th percentile)

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  • Snyk ID SNYK-ALPINE320-XEN-7012654
  • published 23 May 2024
  • disclosed 24 Nov 2021
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Introduced: 24 Nov 2021

CVE-2021-28708 Open this link in a new tab

How to fix?

Upgrade Alpine:3.20 xen to version 4.15.1-r2 or higher.

NVD Description

Note: Versions mentioned in the description apply only to the upstream xen package and not the xen package as distributed by Alpine. See How to fix? for Alpine:3.20 relevant fixed versions and status.

PoD operations on misaligned GFNs T[his CNA information record relates to multiple CVEs; the text explains which aspects/vulnerabilities correspond to which CVE.] x86 HVM and PVH guests may be started in populate-on-demand (PoD) mode, to provide a way for them to later easily have more memory assigned. Guests are permitted to control certain P2M aspects of individual pages via hypercalls. These hypercalls may act on ranges of pages specified via page orders (resulting in a power-of-2 number of pages). The implementation of some of these hypercalls for PoD does not enforce the base page frame number to be suitably aligned for the specified order, yet some code involved in PoD handling actually makes such an assumption. These operations are XENMEM_decrease_reservation (CVE-2021-28704) and XENMEM_populate_physmap (CVE-2021-28707), the latter usable only by domains controlling the guest, i.e. a de-privileged qemu or a stub domain. (Patch 1, combining the fix to both these two issues.) In addition handling of XENMEM_decrease_reservation can also trigger a host crash when the specified page order is neither 4k nor 2M nor 1G (CVE-2021-28708, patch 2).

CVSS Scores

version 3.1
Expand this section

NVD

Recommended
8.8 high
  • Attack Vector (AV)
    Local
  • Attack Complexity (AC)
    Low
  • Privileges Required (PR)
    Low
  • User Interaction (UI)
    None
  • Scope (S)
    Changed
  • Confidentiality (C)
    High
  • Integrity (I)
    High
  • Availability (A)
    High
Expand this section

SUSE

5.5 medium