Kernel crash via unchecked framebuffer dimensions
Published Jul 18, 2022 · Updated Aug 3, 2024
Out-of-bounds write in the Linux Kernel framebuffer console in 5.18 through 5.19-rc5 allows local users to crash the system. The FBIOPUT_VSCREENINFO path accepts screen dimensions that cannot accommodate the active console font, so fbcon rendering writes beyond its vmalloc buffer. Access to a framebuffer device such as /dev/fb0 is required; successful triggering crashes the kernel or executes code in kernel context.
Summary
What happened
Out-of-bounds write in the Linux Kernel framebuffer console in 5.18 through 5.19-rc5 allows local users to crash the system. The FBIOPUT_VSCREENINFO path accepts screen dimensions that cannot accommodate the active console font, so fbcon rendering writes beyond its vmalloc buffer. Access to a framebuffer device such as /dev/fb0 is required; successful triggering crashes the kernel or executes code in kernel context.
The record
- CVE
- CVE-2021-33655
- Published
- Jul 18, 2022
- Updated
- Aug 3, 2024
- Vendor
- The Linux Kernel Organization
- Product
- Linux Kernel
- Classifications
- CWE-787, T1068
- Attack vector
- local
- Privileges
- admin
Timeline
How it unfolded
- Jul 18, 2022CVE publishedPublication date reported by the CVE source.
- Aug 3, 2024Record updatedLatest update available in the CVE record.
Exploitability
Present is not the same as exploitable
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Is a vulnerable build present?
Compare these published version ranges with your installed build and any vendor patches.
- Affected versionversion=5.18 5.19.0-rc1
What conditions does exploitation require?
What is affected?
Attacks
What attackers are doing with it
Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.
Public exploit references
No public exploit references are available in this record.
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Technologies
Your stack
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Your stack
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