ImageMagick MIFF LZMA OOB Write Before 6.9.13-48 / 7.1.2-23
CVE-2026-46521 Published on June 10, 2026
ImageMagick: Heap Buffer Over-Write in MIFF encoder when using LZMA compression
ImageMagick is free and open-source software used for editing and manipulating digital images. Prior to versions 6.9.13-48 and 7.1.2-23, when using LZMA compression in the MIFF encoder an out of bounds write can occur due to a missing check. This issue has been patched in versions 6.9.13-48 and 7.1.2-23.
Vulnerability Analysis
CVE-2026-46521 can be exploited with local system access, requires user interaction. This vulnerability is considered to have a low attack complexity. The potential impact of an exploit of this vulnerability is considered to have no impact on confidentiality and integrity, and a high impact on availability.
Weakness Types
Incorrect Calculation of Buffer Size
The software does not correctly calculate the size to be used when allocating a buffer, which could lead to a buffer overflow.
Unchecked Return Value
The software does not check the return value from a method or function, which can prevent it from detecting unexpected states and conditions. Two common programmer assumptions are "this function call can never fail" and "it doesn't matter if this function call fails". If an attacker can force the function to fail or otherwise return a value that is not expected, then the subsequent program logic could lead to a vulnerability, because the software is not in a state that the programmer assumes. For example, if the program calls a function to drop privileges but does not check the return code to ensure that privileges were successfully dropped, then the program will continue to operate with the higher privileges.
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-2026-46521 has been classified to as a Memory Corruption vulnerability or weakness.
What is an Infinite Loop Vulnerability?
The program contains an iteration or loop with an exit condition that cannot be reached, i.e., an infinite loop. If the loop can be influenced by an attacker, this weakness could allow attackers to consume excessive resources such as CPU or memory.
CVE-2026-46521 has been classified to as an Infinite Loop vulnerability or weakness.
Products Associated with CVE-2026-46521
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Affected Versions
ImageMagick:- Version < 6.9.13-48 is affected.
- Version < 7.1.2-23 is affected.