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CVE-2021-47383 Affecting kernel-64k-debug-modules package, versions <0:5.14.0-427.42.1.el9_4

Severity

 Recommended
medium

Based on AlmaLinux security rating

    Threat Intelligence

    EPSS
    0.04% (15th percentile)

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  • Snyk ID SNYK-ALMALINUX9-KERNEL64KDEBUGMODULES-8333777
  • published 4 Nov 2024
  • disclosed 30 Oct 2024
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Introduced: 30 Oct 2024

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How to fix?

Upgrade AlmaLinux:9 kernel-64k-debug-modules to version 0:5.14.0-427.42.1.el9_4 or higher.
This issue was patched in ALSA-2024:8617.

NVD Description

Note: Versions mentioned in the description apply only to the upstream kernel-64k-debug-modules package and not the kernel-64k-debug-modules package as distributed by AlmaLinux. See How to fix? for AlmaLinux:9 relevant fixed versions and status.

In the Linux kernel, the following vulnerability has been resolved:

tty: Fix out-of-bound vmalloc access in imageblit

This issue happens when a userspace program does an ioctl FBIOPUT_VSCREENINFO passing the fb_var_screeninfo struct containing only the fields xres, yres, and bits_per_pixel with values.

If this struct is the same as the previous ioctl, the vc_resize() detects it and doesn't call the resize_screen(), leaving the fb_var_screeninfo incomplete. And this leads to the updatescrollmode() calculates a wrong value to fbcon_display->vrows, which makes the real_y() return a wrong value of y, and that value, eventually, causes the imageblit to access an out-of-bound address value.

To solve this issue I made the resize_screen() be called even if the screen does not need any resizing, so it will "fix and fill" the fb_var_screeninfo independently.

References

CVSS Scores

version 3.1
Expand this section

Red Hat

6.6 medium
  • Attack Vector (AV)
    Local
  • Attack Complexity (AC)
    Low
  • Privileges Required (PR)
    Low
  • User Interaction (UI)
    None
  • Scope (S)
    Unchanged
  • Confidentiality (C)
    Low
  • Integrity (I)
    Low
  • Availability (A)
    High
Expand this section

SUSE

7.8 high