CVE-2021-47383: tty: Fix out-of-bound vmalloc access in imageblit
In the Linux kernel, the following vulnerability has been resolved:
tty: Fix out-of-bound vmalloc access in imageblit
The Linux kernel CVE team has assigned CVE-2021-47383 to this issue.
Upstream advisory: https://lore.kernel.org/linux-cve-announce/2024052144-CVE-2021-47383-a8f4@gregkh/T
Other sources
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 FBIOPUTVSCREENINFO passing the fbvarscreeninfo struct containing only the fields xres, yres, and bitsperpixel with values.
If this struct is the same as the previous ioctl, the vcresize() detects it and doesn't call the resizescreen(), leaving the fbvarscreeninfo incomplete. And this leads to the updatescrollmode() calculates a wrong value to fbcondisplay->vrows, which makes the realy() 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 resizescreen() be called even if the screen does not need any resizing, so it will "fix and fill" the fbvarscreeninfo independently.
— NVD
Linux Kernel could allow a local authenticated attacker to execute arbitrary code on the system, caused by an out-of-bound vmalloc access flaw in imageblit. By sending a specially crafted request, an attacker could exploit this vulnerability to execute arbitrary code on the system.
— IBM
Affected Software
Remediation
Event History
Frequently Asked Questions
What is the severity of CVE-2021-47383?
CVE-2021-47383 has been classified as a medium severity vulnerability due to its potential for out-of-bound memory access.
How do I fix CVE-2021-47383?
To mitigate CVE-2021-47383, update your Linux kernel to a version that is patched, such as 4.4.286, 4.9.285, 4.14.249, 4.19.209, 5.4.151, 5.10.71, 5.14.10, or 5.15.
What systems are affected by CVE-2021-47383?
CVE-2021-47383 affects specific versions of the Linux kernel as well as IBM Security Verify Governance and its related products up to version ISVG 10.0.2.
What type of vulnerability is CVE-2021-47383?
CVE-2021-47383 is an out-of-bounds memory access vulnerability found in the Linux kernel's tty subsystem.
Can CVE-2021-47383 lead to remote exploitation?
There is a potential risk that CVE-2021-47383 could be leveraged for remote exploitation depending on the context of use and existing security measures.