CVE-2026-42311 Pillow PSD memory corruption before 12.2.0
CVE-2026-42311 Published on May 9, 2026
Pillow: OOB Write with Invalid PSD Tile Extents (Integer Overflow)
Pillow is a Python imaging library. From version 10.3.0 to before version 12.2.0, processing a malicious PSD file could lead to memory corruption, potentially resulting in a crash or arbitrary code execution. This issue has been patched in version 12.2.0.
Weakness Types
Integer Overflow or Wraparound
The software performs a calculation that can produce an integer overflow or wraparound, when the logic assumes that the resulting value will always be larger than the original value. This can introduce other weaknesses when the calculation is used for resource management or execution control. An integer overflow or wraparound occurs when an integer value is incremented to a value that is too large to store in the associated representation. When this occurs, the value may wrap to become a very small or negative number. While this may be intended behavior in circumstances that rely on wrapping, it can have security consequences if the wrap is unexpected. This is especially the case if the integer overflow can be triggered using user-supplied inputs. This becomes security-critical when the result is used to control looping, make a security decision, or determine the offset or size in behaviors such as memory allocation, copying, concatenation, etc.
What is a Memory Corruption Vulnerability?
The software writes data past the end, or before the beginning, of the intended buffer. Typically, this can result in corruption of data, a crash, or code execution. The software may modify an index or perform pointer arithmetic that references a memory location that is outside of the boundaries of the buffer. A subsequent write operation then produces undefined or unexpected results.
CVE-2026-42311 has been classified to as a Memory Corruption vulnerability or weakness.