Bug 2108696 (CVE-2021-33656) - CVE-2021-33656 kernel: when setting font with malicious data by ioctl PIO_FONT, kernel will write memory out of bounds
Summary: CVE-2021-33656 kernel: when setting font with malicious data by ioctl PIO_FON...
Keywords:
Status: CLOSED ERRATA
Alias: CVE-2021-33656
Product: Security Response
Classification: Other
Component: vulnerability
Version: unspecified
Hardware: All
OS: Linux
medium
medium
Target Milestone: ---
Assignee: Red Hat Product Security
QA Contact:
URL:
Whiteboard:
Depends On: 2109148 2109164 2109165 2109166 2109167 2224517 2225155
Blocks: 2108340
TreeView+ depends on / blocked
 
Reported: 2022-07-19 17:46 UTC by Alex
Modified: 2023-09-06 21:48 UTC (History)
50 users (show)

Fixed In Version: Kernel 5.12
Doc Type: If docs needed, set a value
Doc Text:
An out-of-bounds write flaw was found in the Linux kernel’s console driver functionality in the way a user triggers the ioctl PIO_FONT with malicious data. This flaw allows a local user to crash or potentially escalate their privileges on the system.
Clone Of:
Environment:
Last Closed: 2023-05-16 19:11:21 UTC
Embargoed:

Attachments (Terms of Use)


Links
System ID Private Priority Status Summary Last Updated
Red Hat Product Errata RHSA-2023:2736 0 None None None 2023-05-16 08:04:45 UTC
Red Hat Product Errata RHSA-2023:2951 0 None None None 2023-05-16 08:33:37 UTC
Red Hat Product Errata RHSA-2023:4789 0 None None None 2023-08-29 08:43:58 UTC

Description Alex 2022-07-19 17:46:29 UTC 
A flaw in the Linux Kernel console driver found. When setting font with malicious data by ioctl PIO_FONT, kernel will write memory out of bounds. To trigger the vulnerability user need to have access to console driver like if text mode being used through a generic VGA standard display.

Reference:
https://git.kernel.org/pub/scm/linux/kernel/git/stable/stable-queue.git/tree/releases/5.10.127/vt-drop-old-font-ioctls.patch
Comment 2 Alex 2022-07-20 14:15:54 UTC 
Created kernel tracking bugs for this issue:

Affects: fedora-all [bug 2109148]
Comment 5 Justin M. Forbes 2022-07-22 18:35:24 UTC 
This was fixed for Fedora with the 5.12 stable kernel rebases.
Comment 11 errata-xmlrpc 2023-05-16 08:04:41 UTC 
This issue has been addressed in the following products:

  Red Hat Enterprise Linux 8

Via RHSA-2023:2736 https://access.redhat.com/errata/RHSA-2023:2736
Comment 12 errata-xmlrpc 2023-05-16 08:33:33 UTC 
This issue has been addressed in the following products:

  Red Hat Enterprise Linux 8

Via RHSA-2023:2951 https://access.redhat.com/errata/RHSA-2023:2951
Comment 13 Product Security DevOps Team 2023-05-16 19:11:17 UTC 
This bug is now closed. Further updates for individual products will be reflected on the CVE page(s):

https://access.redhat.com/security/cve/cve-2021-33656
Comment 22 errata-xmlrpc 2023-08-29 08:43:55 UTC 
This issue has been addressed in the following products:

  Red Hat Enterprise Linux 8.6 Extended Update Support

Via RHSA-2023:4789 https://access.redhat.com/errata/RHSA-2023:4789
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