Linux Kernel up to 7.1.9 fbdev show_modes buffer overflow

Summaryinfo

A vulnerability labeled as very critical has been found in Linux Kernel up to 7.1.9. Affected by this issue is the function show_modes of the component fbdev. Executing a manipulation can lead to buffer overflow. This vulnerability is tracked as CVE-2026-80580. The attack can be launched remotely. No exploit exists. The affected component should be upgraded.

Detailsinfo

A vulnerability classified as very critical was found in Linux Kernel up to 7.1.9. This vulnerability affects the function show_modes of the component fbdev. The manipulation with an unknown input leads to a buffer overflow vulnerability. The CWE definition for the vulnerability is CWE-120. The product copies an input buffer to an output buffer without verifying that the size of the input buffer is less than the size of the output buffer, leading to a buffer overflow. As an impact it is known to affect confidentiality, integrity, and availability. CVE summarizes:

In the Linux kernel, the following vulnerability has been resolved: fbdev: bound mode sysfs output to the sysfs buffer mode_string() uses snprintf() which can return a value larger than the remaining buffer space. show_modes() accumulates the return value into i without checking whether i has reached PAGE_SIZE, causing the offset to advance past the sysfs buffer if the modelist is long enough. Add a size parameter to mode_string() and use scnprintf() to return only the bytes actually written. Add an early return when offset already exceeds the buffer. In show_modes(), stop accumulating once the buffer is full.

The advisory is available at git.kernel.org. This vulnerability was named CVE-2026-80580 since 08/26/2026. The exploitation appears to be easy. The attack can be initiated remotely. Technical details are known, but there is no available exploit. The structure of the vulnerability defines a possible price range of USD $5k-$25k at the moment (estimation calculated on 08/26/2026).

Upgrading to version 7.1.10 eliminates this vulnerability. Applying the patch 873a1aa15c313263f2e18b38cf525623cc4fabf6 is able to eliminate this problem. The best possible mitigation is suggested to be upgrading to the latest version.

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Productinfo

Type

• Operating System

Vendor

• Linux

Name

• Kernel

Version

• 7.1.0
• 7.1.1
• 7.1.2
• 7.1.3
• 7.1.4
• 7.1.5
• 7.1.6
• 7.1.7
• 7.1.8
• 7.1.9

License

• open-source

Website

• Vendor: https://www.kernel.org/

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