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Debian LinuxOperating system · Debian

CVE-2022-23037

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

This is a race condition vulnerability in the Linux PV (Paravirtualization) netfront driver. The driver incorrectly assumes that removing granted access will always succeed after checking that a grant reference is no longer in use. A malicious backend can map the granted page between the check and removal operations, allowing it to retain access to guest memory pages after they should have been revoked, leading to potential data leaks, data corruption, or denial of service.

MitigationApply the upstream Linux kernel patches that fix the grant table race conditions in netfront and related PV drivers. Ensure backends are trusted, as exploitation requires a malicious or compromised backend.

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. Identify if the system is running as a Xen paravirtualized guest
    Run 'xl info' or 'xen-detect' or check 'dmesg | grep -i xen' for Xen-specific boot messages
    Affected if The system is running as a Xen PV guest and uses the netfront network driver
  2. Verify the netfront driver is loaded and active
    Run 'lsmod | grep xen_netfront' or check 'ip link show' for xen* network interfaces
    Affected if The xen_netfront module is loaded and active, indicating PV network usage
  3. Check the running kernel version
    Run 'uname -r' to get the kernel version, then compare against the version that includes the upstream fix for grant table race conditions in netfront
    Affected if The kernel version predates the fix for CVE-2022-23037 in the netfront driver
  4. Confirm Debian version if on Debian
    Run 'cat /etc/debian_version' to verify if the system is Debian 9.0 specifically
    Affected if The system is Debian 9.0 (which is listed as affected)
  5. Inspect Xen grant table usage for netfront
    Check /proc/xen/balloon or review hypervisor logs for grant reference activity related to network devices
    Affected if The system uses grant references for network I/O which is the attack surface for this vulnerability

A user is affected if they are running a Linux guest as a Xen paravirtualized instance with the netfront driver active and their kernel version is older than the fixed version containing the grant table race condition patch.

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.

dbcve · scoped
Mitigation available No clean upgrade yet — mitigate in the meantime
Mitigation

Apply the upstream Linux kernel patches that fix the grant table race conditions in netfront and related PV drivers. Ensure backends are trusted, as exploitation requires a malicious or compromised backend.

Recommended fix Moderate confidence

Linux kernel version containing the fix for CVE-2022-23037 (check distribution security advisories for exact version); Debian 9.0 receives fixes via DSA (Debian Security Advisory) updates

  1. Update the Linux kernel to a version that includes the fix for the netfront grant table race condition (CVE-2022-23037). The fix involves proper synchronization when checking grant reference usage and removing granted access to prevent the race condition.
  2. For Debian 9.0 systems, apply the Debian security update that addresses this CVE. This typically involves upgrading the kernel package via 'apt-get update && apt-get upgrade' or 'apt-get dist-upgrade', followed by a system reboot.
  3. For Xen environments, ensure both dom0 kernel and any PV guest kernels are updated. The fix requires updates to the Linux kernel running as the PV frontend (typically in domU guests).
  4. After updating, verify the kernel version includes the fix by checking the changelog for CVE-2022-23037 or checking the kernel version against known fixed releases.
  5. Reboot the system to load the updated kernel.
Caveat Kernel updates may require system reboot and could have compatibility implications with custom kernel modules or specific hardware drivers

Generated from the published advisory — verify against the referenced sources before acting.

Fix this in Debian Linux Scoped from the published advisory
  • Consultation2.0 h
  • Implementation4.0 h
  • Testing2.0 h
  • Review / QA1.0 h
9.0 hours of engineering $1,600
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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-2022-23037 in production — separate from our analysis above.

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What this is

A place for practitioners to share what actually worked: a mitigation you’ve tested, a configuration change, a version- or environment-specific caveat, or a link to a verified patch. The most useful notes rise to the top as peers upvote them, so the signal stays high.

What belongs here
  • Verified mitigations, workarounds, and config changes
  • Version or environment caveats, and links to real fixes
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