CVE-2026-63949
Description
A flaw was found in the Linux kernel's auxdisplay line-display subsystem. A local user can trigger an out-of-bounds read by writing a zero-length message to the message sysfs attribute. This occurs because the linedisp_display() function attempts to read a character from a zero-length buffer, leading to an out-of-bounds memory access. On kernels with Kernel Address Sanitizer (KASAN) enabled, this can cause a system panic, resulting in a denial of service. This vulnerability affects various auxdisplay drivers, including ht16k33, max6959, img-ascii-lcd, and seg-led-gpio.
Understanding the Weakness (CWE)
Confidentiality
Technical Impact: Read Memory
An attacker could get secret values such as cryptographic keys, PII, memory addresses, or other information that could be used in additional attacks.
Confidentiality
Technical Impact: Bypass Protection Mechanism
Out-of-bounds memory could contain memory addresses or other information that can be used to bypass ASLR and other protection mechanisms in order to improve the reliability of exploiting a separate weakness for code execution.
Availability
Technical Impact: DoS: Crash, Exit, or Restart
An attacker could cause a segmentation fault or crash by causing memory to be read outside of the bounds of the buffer. This is especially likely when the code reads a variable amount of data and assumes that a sentinel exists to stop the read operation, such as a NUL in a string.
Other
Technical Impact: Varies by Context
The read operation could produce other undefined or unexpected results.
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