CVE-2022-33745

Host denial of service via omitted TLB flushes

Published Jul 26, 2022 · Updated Aug 3, 2024

Denial of service in Xen versions with XSA-401 fixes allows guest OS users to exhaust host memory through x86 PV shadow paging. Relocated code tests a variable whose meaning changed at the new position, causing the shadow-paging logic to omit required TLB flushes. Exploitation requires an x86 PV guest in shadow mode during migration or as an L1TF workaround; the observed consequence is a host-wide service interruption from memory exhaustion.

CVSS severity8.8
High
EPSS probability0.30%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Denial of service in Xen versions with XSA-401 fixes allows guest OS users to exhaust host memory through x86 PV shadow paging. Relocated code tests a variable whose meaning changed at the new position, causing the shadow-paging logic to omit required TLB flushes. Exploitation requires an x86 PV guest in shadow mode during migration or as an L1TF workaround; the observed consequence is a host-wide service interruption from memory exhaustion.

The record

CVE
CVE-2022-33745
Published
Jul 26, 2022
Updated
Aug 3, 2024
Vendor
Unknown vendor
Product
Unknown product
Classifications
T1499.004
Attack vector
local
Privileges
authenticated

Timeline

How it unfolded

  1. Jul 26, 2022CVE publishedPublication date reported by the CVE source.
  2. Aug 3, 2024Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Affected buildAffected product and version details are unavailable.

What conditions does exploitation require?

Attack vectorlocal
Required privilegesauthenticated

What is affected?

Affected products and versions are unavailable in this record.

Published CVSS scores

8.8UbuntuCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

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No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectorlocal
Privilegesauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

T1499.004Endpoint Denial of Service: Application or System Exploitation

Public exploit references

No public exploit references are available in this record.

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

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Your stack

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