// For flags

CVE-2021-3656

kernel: SVM nested virtualization issue in KVM (VMLOAD/VMSAVE)

Severity Score

8.8
*CVSS v3.1

Exploit Likelihood

*EPSS

Affected Versions

*CPE

Public Exploits

1
*Multiple Sources

Exploited in Wild

-
*KEV

Decision

-
*SSVC
Descriptions

A flaw was found in the KVM's AMD code for supporting SVM nested virtualization. The flaw occurs when processing the VMCB (virtual machine control block) provided by the L1 guest to spawn/handle a nested guest (L2). Due to improper validation of the "virt_ext" field, this issue could allow a malicious L1 to disable both VMLOAD/VMSAVE intercepts and VLS (Virtual VMLOAD/VMSAVE) for the L2 guest. As a result, the L2 guest would be allowed to read/write physical pages of the host, resulting in a crash of the entire system, leak of sensitive data or potential guest-to-host escape.

Se ha encontrado un fallo en el código AMD de KVM para soportar la virtualización anidada SVM. El fallo es producido cuando es procesado el VMCB (bloque de control de la máquina virtual) proporcionado por el huésped L1 para generar/manejar un huésped anidado (L2). Debido a que no es comprobado apropiadamente el campo "virt_ext", este problema podría permitir a un L1 malicioso deshabilitar tanto las intercepciones VMLOAD/VMSAVE como el VLS (Virtual VMLOAD/VMSAVE) para el huésped L2. Como resultado, el invitado L2 podría leer/escribir páginas físicas del anfitrión, resultando en un bloqueo de todo el sistema, un filtrado de datos confidenciales o un potencial escape del invitado al anfitrión

*Credits: N/A
CVSS Scores
Attack Vector
Local
Attack Complexity
Low
Privileges Required
Low
User Interaction
None
Scope
Changed
Confidentiality
High
Integrity
High
Availability
High
Attack Vector
Local
Attack Complexity
Low
Authentication
None
Confidentiality
Complete
Integrity
Complete
Availability
Complete
* Common Vulnerability Scoring System
SSVC
  • Decision:-
Exploitation
-
Automatable
-
Tech. Impact
-
* Organization's Worst-case Scenario
Timeline
  • 2021-07-21 CVE Reserved
  • 2021-09-09 CVE Published
  • 2022-11-22 First Exploit
  • 2023-03-08 EPSS Updated
  • 2024-08-03 CVE Updated
  • ---------- Exploited in Wild
  • ---------- KEV Due Date
CWE
  • CWE-862: Missing Authorization
CAPEC
Affected Vendors, Products, and Versions
Vendor Product Version Other Status
Vendor Product Version Other Status <-- --> Vendor Product Version Other Status
Redhat
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Software Collections
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Affected
in Redhat
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Enterprise Linux Server
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7.0
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-
Safe
Redhat
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3scale Api Management
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2.0
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-
Affected
in Redhat
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Enterprise Linux
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7.0
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-
Safe
Redhat
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3scale Api Management
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2.0
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-
Affected
in Redhat
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Enterprise Linux
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8.0
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-
Safe
Redhat
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Codeready Linux Builder
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--
Affected
in Redhat
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Enterprise Linux
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8.0
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-
Safe
Redhat
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Codeready Linux Builder
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--
Affected
in Redhat
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Enterprise Linux Eus
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8.1
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-
Safe
Redhat
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Codeready Linux Builder
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--
Affected
in Redhat
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Enterprise Linux Eus
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8.2
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-
Safe
Redhat
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Codeready Linux Builder
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--
Affected
in Redhat
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Enterprise Linux Eus
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8.4
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-
Safe
Redhat
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Codeready Linux Builder
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--
Affected
in Redhat
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Enterprise Linux For Power Little Endian
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8.0
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-
Safe
Redhat
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Codeready Linux Builder
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--
Affected
in Redhat
Search vendor "Redhat"
Enterprise Linux For Power Little Endian Eus
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8.1
Search vendor "Redhat" for product "Enterprise Linux For Power Little Endian Eus" and version "8.1"
-
Safe
Redhat
Search vendor "Redhat"
Codeready Linux Builder
Search vendor "Redhat" for product "Codeready Linux Builder"
--
Affected
in Redhat
Search vendor "Redhat"
Enterprise Linux For Power Little Endian Eus
Search vendor "Redhat" for product "Enterprise Linux For Power Little Endian Eus"
8.2
Search vendor "Redhat" for product "Enterprise Linux For Power Little Endian Eus" and version "8.2"
-
Safe
Redhat
Search vendor "Redhat"
Codeready Linux Builder
Search vendor "Redhat" for product "Codeready Linux Builder"
--
Affected
in Redhat
Search vendor "Redhat"
Enterprise Linux For Power Little Endian Eus
Search vendor "Redhat" for product "Enterprise Linux For Power Little Endian Eus"
8.4
Search vendor "Redhat" for product "Enterprise Linux For Power Little Endian Eus" and version "8.4"
-
Safe
Redhat
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Virtualization Host
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4.0
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-
Affected
in Redhat
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Enterprise Linux
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7.0
Search vendor "Redhat" for product "Enterprise Linux" and version "7.0"
-
Safe
Redhat
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Virtualization Host
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4.0
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-
Affected
in Redhat
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Enterprise Linux
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8.0
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-
Safe
Linux
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Linux Kernel
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>= 4.13 < 4.14.245
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-
Affected
Linux
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Linux Kernel
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>= 4.15 < 4.19.205
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-
Affected
Linux
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Linux Kernel
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>= 4.20 < 5.4.142
Search vendor "Linux" for product "Linux Kernel" and version " >= 4.20 < 5.4.142"
-
Affected
Linux
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Linux Kernel
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>= 5.5 < 5.10.60
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Affected
Linux
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Linux Kernel
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>= 5.11 < 5.13.12
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Affected
Linux
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Linux Kernel
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5.14
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-
Affected
Linux
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Linux Kernel
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5.14
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rc1
Affected
Linux
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Linux Kernel
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5.14
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rc2
Affected
Linux
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Linux Kernel
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5.14
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rc3
Affected
Linux
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Linux Kernel
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5.14
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rc4
Affected
Linux
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Linux Kernel
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5.14
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rc5
Affected
Linux
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Linux Kernel
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5.14
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rc6
Affected
Fedoraproject
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Fedora
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33
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Affected
Fedoraproject
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Fedora
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34
Search vendor "Fedoraproject" for product "Fedora" and version "34"
-
Affected
Redhat
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Openstack
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13
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-
Affected
Redhat
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Enterprise Linux
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8.0
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-
Affected
Redhat
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Enterprise Linux Desktop
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7.0
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Affected
Redhat
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Enterprise Linux Eus
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8.1
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Affected
Redhat
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Enterprise Linux Eus
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8.2
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Affected
Redhat
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Enterprise Linux Eus
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8.4
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Affected
Redhat
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Enterprise Linux For Ibm Z Systems
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7.0
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-
Affected
Redhat
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Enterprise Linux For Ibm Z Systems
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8.0
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Affected
Redhat
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Enterprise Linux For Ibm Z Systems Eus
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8.1
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Affected
Redhat
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Enterprise Linux For Ibm Z Systems Eus
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8.2
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Affected
Redhat
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Enterprise Linux For Ibm Z Systems Eus
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8.4
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Affected
Redhat
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Enterprise Linux For Power Big Endian
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7.0
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-
Affected
Redhat
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Enterprise Linux For Power Little Endian
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7.0
Search vendor "Redhat" for product "Enterprise Linux For Power Little Endian" and version "7.0"
-
Affected
Redhat
Search vendor "Redhat"
Enterprise Linux For Power Little Endian
Search vendor "Redhat" for product "Enterprise Linux For Power Little Endian"
8.0
Search vendor "Redhat" for product "Enterprise Linux For Power Little Endian" and version "8.0"
-
Affected
Redhat
Search vendor "Redhat"
Enterprise Linux For Power Little Endian Eus
Search vendor "Redhat" for product "Enterprise Linux For Power Little Endian Eus"
8.1
Search vendor "Redhat" for product "Enterprise Linux For Power Little Endian Eus" and version "8.1"
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Affected
Redhat
Search vendor "Redhat"
Enterprise Linux For Power Little Endian Eus
Search vendor "Redhat" for product "Enterprise Linux For Power Little Endian Eus"
8.2
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-
Affected
Redhat
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Enterprise Linux For Power Little Endian Eus
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8.4
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-
Affected
Redhat
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Enterprise Linux For Real Time
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7
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-
Affected
Redhat
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Enterprise Linux For Real Time
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8
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-
Affected
Redhat
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Enterprise Linux For Real Time For Nfv
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7
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-
Affected
Redhat
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Enterprise Linux For Real Time For Nfv
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8
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Affected
Redhat
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Enterprise Linux For Real Time For Nfv Tus
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8.2
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-
Affected
Redhat
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Enterprise Linux For Real Time For Nfv Tus
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8.4
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-
Affected
Redhat
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Enterprise Linux For Real Time Tus
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8.2
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-
Affected
Redhat
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Enterprise Linux For Real Time Tus
Search vendor "Redhat" for product "Enterprise Linux For Real Time Tus"
8.4
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-
Affected
Redhat
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Enterprise Linux For Scientific Computing
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7.0
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Affected
Redhat
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Enterprise Linux Server
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7.0
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Affected
Redhat
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Enterprise Linux Server Aus
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7.6
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Affected
Redhat
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Enterprise Linux Server Aus
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7.7
Search vendor "Redhat" for product "Enterprise Linux Server Aus" and version "7.7"
-
Affected
Redhat
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Enterprise Linux Server Aus
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8.2
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-
Affected
Redhat
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Enterprise Linux Server Aus
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8.4
Search vendor "Redhat" for product "Enterprise Linux Server Aus" and version "8.4"
-
Affected
Redhat
Search vendor "Redhat"
Enterprise Linux Server For Power Little Endian Update Services For Sap Solutions
Search vendor "Redhat" for product "Enterprise Linux Server For Power Little Endian Update Services For Sap Solutions"
7.6
Search vendor "Redhat" for product "Enterprise Linux Server For Power Little Endian Update Services For Sap Solutions" and version "7.6"
-
Affected
Redhat
Search vendor "Redhat"
Enterprise Linux Server For Power Little Endian Update Services For Sap Solutions
Search vendor "Redhat" for product "Enterprise Linux Server For Power Little Endian Update Services For Sap Solutions"
8.1
Search vendor "Redhat" for product "Enterprise Linux Server For Power Little Endian Update Services For Sap Solutions" and version "8.1"
-
Affected
Redhat
Search vendor "Redhat"
Enterprise Linux Server For Power Little Endian Update Services For Sap Solutions
Search vendor "Redhat" for product "Enterprise Linux Server For Power Little Endian Update Services For Sap Solutions"
8.2
Search vendor "Redhat" for product "Enterprise Linux Server For Power Little Endian Update Services For Sap Solutions" and version "8.2"
-
Affected
Redhat
Search vendor "Redhat"
Enterprise Linux Server For Power Little Endian Update Services For Sap Solutions
Search vendor "Redhat" for product "Enterprise Linux Server For Power Little Endian Update Services For Sap Solutions"
8.4
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-
Affected
Redhat
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Enterprise Linux Server Tus
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7.6
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-
Affected
Redhat
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Enterprise Linux Server Tus
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7.7
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Affected
Redhat
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Enterprise Linux Server Tus
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8.2
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Affected
Redhat
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Enterprise Linux Server Tus
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8.4
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Affected
Redhat
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Enterprise Linux Server Update Services For Sap Solutions
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7.6
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-
Affected
Redhat
Search vendor "Redhat"
Enterprise Linux Server Update Services For Sap Solutions
Search vendor "Redhat" for product "Enterprise Linux Server Update Services For Sap Solutions"
7.7
Search vendor "Redhat" for product "Enterprise Linux Server Update Services For Sap Solutions" and version "7.7"
-
Affected
Redhat
Search vendor "Redhat"
Enterprise Linux Server Update Services For Sap Solutions
Search vendor "Redhat" for product "Enterprise Linux Server Update Services For Sap Solutions"
8.1
Search vendor "Redhat" for product "Enterprise Linux Server Update Services For Sap Solutions" and version "8.1"
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Affected
Redhat
Search vendor "Redhat"
Enterprise Linux Server Update Services For Sap Solutions
Search vendor "Redhat" for product "Enterprise Linux Server Update Services For Sap Solutions"
8.2
Search vendor "Redhat" for product "Enterprise Linux Server Update Services For Sap Solutions" and version "8.2"
-
Affected
Redhat
Search vendor "Redhat"
Enterprise Linux Server Update Services For Sap Solutions
Search vendor "Redhat" for product "Enterprise Linux Server Update Services For Sap Solutions"
8.4
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Affected
Redhat
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Enterprise Linux Workstation
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7.0
Search vendor "Redhat" for product "Enterprise Linux Workstation" and version "7.0"
-
Affected