CVE-2021-46904

Aliases:UBUNTU-CVE-2021-46904DEBIAN-CVE-2021-46904
Advisory lineage Upstream: 0 Downstream: 11
Modified
Published: 25 Feb 2024, 14:03
Last modified:11 May 2026, 13:44

Vulnerability Summary

Overall Risk (default)
low
22/100
CVSS Score
5.5 MEDIUM
v3.1 (nvd)
EPSS Score
0.26% LOW
0% probability +0.24%
KEV
Not listed
Ransomware
No reports
Public exploits
None found
Dark Web
Not detected

Timeline

25 Feb 2024, 14:03
Published
Vulnerability first disclosed
11 May 2026, 13:44
Last Modified
Vulnerability information updated

Description

In the Linux kernel, the following vulnerability has been resolved: net: hso: fix null-ptr-deref during tty device unregistration Multiple ttys try to claim the same the minor number causing a double unregistration of the same device. The first unregistration succeeds but the next one results in a null-ptr-deref. The get_free_serial_index() function returns an available minor number but doesn't assign it immediately. The assignment is done by the caller later. But before this assignment, calls to get_free_serial_index() would return the same minor number. Fix this by modifying get_free_serial_index to assign the minor number immediately after one is found to be and rename it to obtain_minor() to better reflect what it does. Similary, rename set_serial_by_index() to release_minor() and modify it to free up the minor number of the given hso_serial. Every obtain_minor() should have corresponding release_minor() call.

CVSS Metrics

  • v3.1•MEDIUM•Score: 5.5CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H

EPSS Trends

Current EPSS score: 0.26%• Percentile: 18%

Techniques & Countermeasures

  • CWE-476•NULL Pointer Dereference

    The product dereferences a pointer that it expects to be valid but is NULL.

Affected Systems

  • debian•linux

    < 5.10.38-1 | < 5.10.38-1 | < 5.10.38-1 | < 5.10.38-1

  • ubuntu•linux

    < 3.13.0-199.250 | < 4.4.0-258.292 | < 4.15.0-144.148 | < 5.4.0-74.83

  • ubuntu•linux-allwinner-5.19

    all

  • ubuntu•linux-aws

    < 4.4.0-1135.141 | < 4.4.0-1173.188 | < 4.15.0-1103.110 | < 5.4.0-1049.51

  • ubuntu•linux-aws-5.0

    all

  • ubuntu•linux-aws-5.11

    all

  • ubuntu•linux-aws-5.13

    all

  • ubuntu•linux-aws-5.19

    all

  • ubuntu•linux-aws-5.3

    all

  • ubuntu•linux-aws-5.4

    < 5.4.0-1049.51~18.04.1

  • ubuntu•linux-aws-5.8

    all

  • ubuntu•linux-aws-6.2

    all

  • ubuntu•linux-aws-fips

    < 4.15.0-2045.47 | all | < 5.4.0-1069.73+fips2

  • ubuntu•linux-aws-hwe

    < 4.15.0-1103.110~16.04.1

  • ubuntu•linux-azure

    < 4.15.0-1115.128~14.04.1 | < 4.15.0-1115.128~16.04.1 | all | < 5.4.0-1048.50

  • ubuntu•linux-azure-4.15

    < 4.15.0-1115.128

  • ubuntu•linux-azure-5.11

    all

  • ubuntu•linux-azure-5.13

    all

  • ubuntu•linux-azure-5.19

    all

  • ubuntu•linux-azure-5.3

    all

  • ubuntu•linux-azure-5.4

    < 5.4.0-1048.50~18.04.1

  • ubuntu•linux-azure-5.8

    all

  • ubuntu•linux-azure-6.2

    all

  • ubuntu•linux-azure-edge

    all

  • ubuntu•linux-azure-fde

    all

  • ubuntu•linux-azure-fde-5.19

    all

  • ubuntu•linux-azure-fde-6.2

    all

  • ubuntu•linux-azure-fips

    < 4.15.0-2027.30 | all | < 5.4.0-1073.76+fips1

  • ubuntu•linux-bluefield

    all | < 5.4.0-1012.15

  • ubuntu•linux-fips

    < 4.4.0-1104.111 | all | < 4.15.0-1060.68

  • ubuntu•linux-gcp

    < 4.15.0-1100.113~16.04.1 | all | < 5.4.0-1044.47

  • ubuntu•linux-gcp-4.15

    < 4.15.0-1100.113

  • ubuntu•linux-gcp-5.11

    all

  • ubuntu•linux-gcp-5.13

    all

  • ubuntu•linux-gcp-5.19

    all

  • ubuntu•linux-gcp-5.3

    all

  • ubuntu•linux-gcp-5.4

    < 5.4.0-1044.47~18.04.2

  • ubuntu•linux-gcp-5.8

    all

  • ubuntu•linux-gcp-6.2

    all

  • ubuntu•linux-gcp-fips

    all | < 5.4.0-1067.71~20.04.1

  • ubuntu•linux-gke

    all

  • ubuntu•linux-gke-4.15

    all

  • ubuntu•linux-gke-5.15

    all

  • ubuntu•linux-gke-5.4

    all

  • ubuntu•linux-gkeop

    < 5.4.0-1016.17

  • ubuntu•linux-gkeop-5.4

    all

  • ubuntu•linux-hwe

    < 4.15.0-144.148~16.04.1 | all

  • ubuntu•linux-hwe-5.11

    all

  • ubuntu•linux-hwe-5.13

    all

  • ubuntu•linux-hwe-5.19

    all

Showing first 50 affected entries in server-rendered view.

References (14)