// For flags

CVE-2021-4001

Ubuntu Security Notice USN-6417-1

Severity Score

4.1
*CVSS v3.1

Exploit Likelihood

*EPSS

Affected Versions

*CPE

Public Exploits

0
*Multiple Sources

Exploited in Wild

-
*KEV

Decision

-
*SSVC
Descriptions

A race condition was found in the Linux kernel's ebpf verifier between bpf_map_update_elem and bpf_map_freeze due to a missing lock in kernel/bpf/syscall.c. In this flaw, a local user with a special privilege (cap_sys_admin or cap_bpf) can modify the frozen mapped address space. This flaw affects kernel versions prior to 5.16 rc2.

Se ha encontrado una condiciĆ³n de carrera en el verificador ebpf del kernel de Linux entre las funciones bpf_map_update_elem y bpf_map_freeze debido a la falta de un bloqueo en el archivo kernel/bpf/syscall.c. En este fallo, un usuario local con un privilegio especial (cap_sys_admin o cap_bpf) puede modificar el espacio de direcciones mapeado congelado. Este fallo afecta a las versiones del kernel anteriores a 5.16 rc2

Jeremy Cline discovered a use-after-free in the nouveau graphics driver of the Linux kernel during device removal. A privileged or physically proximate attacker could use this to cause a denial of service. It was discovered that the Bluetooth subsystem in the Linux kernel contained a use-after-free vulnerability. A local attacker could use this to cause a denial of service or possibly execute arbitrary code.

*Credits: N/A
CVSS Scores
Attack Vector
Local
Attack Complexity
High
Privileges Required
High
User Interaction
None
Scope
Unchanged
Confidentiality
None
Integrity
High
Availability
None
Attack Vector
Local
Attack Complexity
Medium
Authentication
None
Confidentiality
None
Integrity
Complete
Availability
None
* Common Vulnerability Scoring System
SSVC
  • Decision:-
Exploitation
-
Automatable
-
Tech. Impact
-
* Organization's Worst-case Scenario
Timeline
  • 2021-11-22 CVE Reserved
  • 2022-01-06 CVE Published
  • 2024-08-03 CVE Updated
  • 2025-03-30 EPSS Updated
  • ---------- Exploited in Wild
  • ---------- KEV Due Date
  • ---------- First Exploit
CWE
  • CWE-367: Time-of-check Time-of-use (TOCTOU) Race Condition
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"
<= 5.15
Search vendor "Linux" for product "Linux Kernel" and version " <= 5.15"
-
Affected
Linux
Search vendor "Linux"
Linux Kernel
Search vendor "Linux" for product "Linux Kernel"
5.16
Search vendor "Linux" for product "Linux Kernel" and version "5.16"
rc1
Affected