// For flags

CVE-2020-36557

kernel: race condition between the VT_DISALLOCATE ioctl and closing/opening of ttys, causing a use-after-free in con_shutdown().

Severity Score

5.1
*CVSS v3.1

Exploit Likelihood

*EPSS

Affected Versions

*CPE

Public Exploits

0
*Multiple Sources

Exploited in Wild

-
*KEV

Decision

-
*SSVC
Descriptions

A race condition in the Linux kernel before 5.6.2 between the VT_DISALLOCATE ioctl and closing/opening of ttys could lead to a use-after-free.

Una condición de carrera en el kernel de Linux versiones anteriores a 5.6.2 entre el ioctl VT_DISALLOCATE y el cierre/apertura de ttys podría conllevar a un uso de memoria previamente liberada

A use-after-free flaw was found in the Linux kernel’s Virtual Terminal subsystem in how a user calls the VT_DISALLOCATE ioctl during the closing/opening of ttys. This flaw allows a local user to crash the system.

*Credits: N/A
CVSS Scores
Attack Vector
Local
Attack Complexity
High
Privileges Required
None
User Interaction
None
Scope
Unchanged
Confidentiality
None
Integrity
None
Availability
High
Attack Vector
Local
Attack Complexity
High
Authentication
None
Confidentiality
None
Integrity
None
Availability
Complete
* Common Vulnerability Scoring System
SSVC
  • Decision:-
Exploitation
-
Automatable
-
Tech. Impact
-
* Organization's Worst-case Scenario
Timeline
  • 2022-07-21 CVE Reserved
  • 2022-07-21 CVE Published
  • 2024-08-04 CVE Updated
  • 2025-04-15 EPSS Updated
  • ---------- Exploited in Wild
  • ---------- KEV Due Date
  • ---------- First Exploit
CWE
  • CWE-362: Concurrent Execution using Shared Resource with Improper Synchronization ('Race Condition')
  • CWE-416: Use After Free
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"
 < 5.6.2
Search vendor "Linux" for product "Linux Kernel" and version " < 5.6.2"
-
Affected