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Debian LinuxOperating system · Debian

CVE-2022-23038

HIGH · 7.0 CVSS v3.1 Published 2022-03-10
Mitigation only
No fix yet — a mitigation exists. There is no fixed release. A documented workaround reduces exposure in the meantime.
See remediation →
72/100
Remediation priority · Elevated
Zero-click

Official description Straight from the sourceThe vendor's or NVD's own wording, published unedited. Authoritative, but often terse — it says what broke, rarely what to do.

NVD · unedited
Linux PV device frontends vulnerable to attacks by backends T[his CNA information record relates to multiple CVEs; the text explains which aspects/vulnerabilities correspond to which CVE.] Several Linux PV device frontends are using the grant table interfaces for removing access rights of the backends in ways being subject to race conditions, resulting in potential data leaks, data corruption by malicious backends, and denial of service triggered by malicious backends: blkfront, netfront, scsifront and the gntalloc driver are testing whether a grant reference is still in use. If this is not the case, they assume that a following removal of the granted access will always succeed, which is not true in case the backend has mapped the granted page between those two operations. As a result the backend can keep access to the memory page of the guest no matter how the page will be used after the frontend I/O has finished. The xenbus driver has a similar problem, as it doesn't check the success of removing the granted access of a shared ring buffer. blkfront: CVE-2022-23036 netfront: CVE-2022-23037 scsifront: CVE-2022-23038 gntalloc: CVE-2022-23039 xenbus: CVE-2022-23040 blkfront, netfront, scsifront, usbfront, dmabuf, xenbus, 9p, kbdfront, and pvcalls are using a functionality to delay freeing a grant reference until it is no longer in use, but the freeing of the related data page is not synchronized with dropping the granted access. As a result the backend can keep access to the memory page even after it has been freed and then re-used for a different purpose. CVE-2022-23041 netfront will fail a BUG_ON() assertion if it fails to revoke access in the rx path. This will result in a Denial of Service (DoS) situation of the guest which can be triggered by the backend. CVE-2022-23042

Technical summary Written by usOur analysis, written from the advisory, the CVSS vector and the affected-version data. It adds context the advisory leaves out, and never invents facts that are not in the source.

dbcve analysis · high confidence

CVE-2022-23038 is a race condition vulnerability in the Linux PV scsifront driver. The driver tests whether a grant reference is still in use before removing granted access, but fails to account for the backend potentially mapping the page between the check and removal operations. This allows malicious backends to retain access to guest memory pages after I/O completion, enabling data leaks, data corruption, or denial of service.

MitigationApply Linux kernel updates that fix the grant table handling race conditions in PV frontend drivers. In virtualized environments, ensure backends are trusted and keep hypervisor/dom0 patched.

Verify against the referenced sources before acting — the references below are authoritative for this CVE, this summary is not.

Affected products & versions What the vendor confirmedThe version ranges the vendor confirmed as vulnerable. If your version sits inside a range here, treat yourself as exposed until you have upgraded.

NVD · CPE data
Debian LinuxOperating system
Affected:= 9.0
XenOperating system
Affected:all versions

CVSS breakdown How the score is builtThe industry scoring standard. It rates how the flaw is reached, what it takes to exploit, and what an attacker gains — the score is derived from those, not the other way round.

From the vector
Attack vector
Local
Complexity
High
Privileges
Low
User interaction
None
Scope
Unchanged
Confidentiality
High
Integrity
High
Availability
High

CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:H

Am I affected? How to checkSteps we derive from the advisory and the affected-version data, so you can decide whether this CVE reaches your setup. They are a guide, not a scan — your own configuration is the authority.

dbcve checks

Work through these to decide whether this CVE applies to you.

  1. Verify Xen virtualization is in use
    Check hypervisor type: `xl list` or `xm list` or look for 'Xen' in `/proc/xen/capabilities` or check `dmesg | grep -i xen`
    Affected if System is not running on Xen hypervisor - the scsifront driver is only relevant in Xen PV environments
  2. Confirm scsifront driver is loaded
    Run `lsmod | grep scsifront` or check `modinfo scsifront` to see if the PV SCSI frontend driver is loaded
    Affected if Module is not loaded - the vulnerability only applies when scsifront is active
  3. Check for active PV SCSI devices
    List SCSI devices with `lsscsi` or check `cat /proc/scsi/scsi` and look for Xen virtual SCSI devices, or check `xl block-list <domain>` for attached virtual disks
    Affected if No PV SCSI disks are attached to the domain - without active I/O the race condition cannot be triggered
  4. Identify installed kernel version
    Run `uname -r` or check `/proc/version`
    Affected if Kernel version is older than fixes for this CVE - the vulnerability exists in unpatched Linux kernels running as Xen PV guests

System is affected if it runs as a Xen paravirtualized guest with scsifront loaded and active PV SCSI devices, using an unpatched kernel older than the CVE fixes.

Generated from the published advisory. Verify against your own configuration.

Check your environment

Paste your version and any relevant configuration and it will be compared against the affected criteria above. Do not include secrets or credentials.

AI-assisted, checked against the advisory. Informational, not a guarantee.

Remediation Closing itWhat it takes to close this. Where a vendor fix exists we point at it; where none exists we say so plainly, and can build one. Effort estimates are scoped from the advisory, not from your codebase.

From vendor data
Mitigation available No clean upgrade yet — mitigate in the meantime
Mitigation

Apply Linux kernel updates that fix the grant table handling race conditions in PV frontend drivers. In virtualized environments, ensure backends are trusted and keep hypervisor/dom0 patched.

Fix this in Debian Linux Scoped from the published advisory
  • Consultation4.0 h
  • Implementation8.0 h
  • Testing6.0 h
  • Review / QA3.0 h
21.0 hours of engineering $3,680
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References Go to the primary sourcePrimary sources — vendor advisories, patches and trackers. Where our summary and a reference disagree, the reference wins.

Primary sources

Practitioner notes

Contributed

Peer-ranked notes from engineers who’ve handled CVE-2022-23038 in production — separate from our analysis above.

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What this is

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What belongs here
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  • Version or environment caveats, and links to real fixes
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