// For flags

CVE-2021-34556

Ubuntu Security Notice USN-5096-1

Severity Score

5.5
*CVSS v3.1

Exploit Likelihood

*EPSS

Affected Versions

*CPE

Public Exploits

0
*Multiple Sources

Exploited in Wild

-
*KEV

Decision

-
*SSVC
Descriptions

In the Linux kernel through 5.13.7, an unprivileged BPF program can obtain sensitive information from kernel memory via a Speculative Store Bypass side-channel attack because the protection mechanism neglects the possibility of uninitialized memory locations on the BPF stack.

En el kernel de Linux versiones hasta 5.13.7, un programa BPF sin privilegios puede obtener información confidencial de la memoria del kernel por medio de un ataque de canal lateral Omisión de Almacenamiento Especulativo porque el mecanismo de protección no tiene en cuenta la posibilidad de ubicaciones de memoria no inicializadas en la pila BPF

It was discovered that the f2fs file system in the Linux kernel did not properly validate metadata in some situations. An attacker could use this to construct a malicious f2fs image that, when mounted and operated on, could cause a denial of service or possibly execute arbitrary code. It was discovered that the Infiniband RDMA userspace connection manager implementation in the Linux kernel contained a race condition leading to a use-after-free vulnerability. A local attacker could use this to cause a denial of service or possible execute arbitrary code. Various other issues were also addressed.

*Credits: N/A
CVSS Scores
Attack Vector
Local
Attack Complexity
Low
Privileges Required
Low
User Interaction
None
Scope
Unchanged
Confidentiality
High
Integrity
None
Availability
None
Attack Vector
Local
Attack Complexity
Low
Authentication
None
Confidentiality
Partial
Integrity
None
Availability
None
* Common Vulnerability Scoring System
SSVC
  • Decision:-
Exploitation
-
Automatable
-
Tech. Impact
-
* Organization's Worst-case Scenario
Timeline
  • 2021-06-10 CVE Reserved
  • 2021-08-02 CVE Published
  • 2024-08-04 CVE Updated
  • 2025-03-30 EPSS Updated
  • ---------- Exploited in Wild
  • ---------- KEV Due Date
  • ---------- First Exploit
CWE
  • CWE-203: Observable Discrepancy
CAPEC
Affected Vendors, Products, and Versions
Vendor Product Version Other Status
Vendor Product Version Other Status <-- --> Vendor Product Version Other Status
Linux
Search vendor "Linux"
Linux Kernel
Search vendor "Linux" for product "Linux Kernel"
<= 5.13.7
Search vendor "Linux" for product "Linux Kernel" and version " <= 5.13.7"
-
Affected
Fedoraproject
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Fedora
Search vendor "Fedoraproject" for product "Fedora"
33
Search vendor "Fedoraproject" for product "Fedora" and version "33"
-
Affected
Fedoraproject
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Fedora
Search vendor "Fedoraproject" for product "Fedora"
34
Search vendor "Fedoraproject" for product "Fedora" and version "34"
-
Affected
Debian
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Debian Linux
Search vendor "Debian" for product "Debian Linux"
9.0
Search vendor "Debian" for product "Debian Linux" and version "9.0"
-
Affected