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Debian LinuxOperating system · Debian

CVE-2022-33745

HIGH · 8.8 CVSS v3.1 Published 2022-07-26
Patch available
A vendor patch is available. No clean upgrade release — apply the published patch.
See remediation →
90/100
Remediation priority · Urgent
Zero-click Patch available

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
insufficient TLB flush for x86 PV guests in shadow mode For migration as well as to work around kernels unaware of L1TF (see XSA-273), PV guests may be run in shadow paging mode. To address XSA-401, code was moved inside a function in Xen. This code movement missed a variable changing meaning / value between old and new code positions. The now wrong use of the variable did lead to a wrong TLB flush condition, omitting flushes where such are necessary.

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

A detailed technical summary for this CVE is being prepared.

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:= 11.0
FedoraOperating system
Affected:= 35= 36
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
Low
Privileges
Low
User interaction
None
Scope
Changed
Confidentiality
High
Integrity
High
Availability
High

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

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
Patch available Apply the vendor patch
Vendor patch www.openwall.com →
Recommended fix Moderate confidence

Xen 4.16.x or later stable release; Debian 11.x security updates; Fedora 35/36 updates

  1. For Xen hypervisor hosts: Upgrade Xen to the latest stable version that includes the fix for CVE-2022-33745, typically Xen 4.16.x or later stable releases
  2. For Debian 11.0 systems: Run 'apt-get update && apt-get upgrade' to apply Debian security updates for the Xen packages
  3. For Fedora 35/36 systems: Run 'dnf update' to apply Fedora security updates for the Xen packages
  4. After upgrading Xen, reboot the host to load the new hypervisor
  5. Verify the Xen version after reboot matches a patched release using 'xl info' or 'xm info'
Caveat Rebooting the Xen host is required to apply the hypervisor update, causing VM downtime. Ensure VMs are properly shut down or migrated before rebooting.

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

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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-2022-33745 in production — separate from our analysis above.

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What this is

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