OpenEXR <8.0 EXR Decoding DWAA/DWAB Channel Size Assumption Vulner
CVE-2025-59733 Published on October 6, 2025
Heap-buffer-overflow write in FFmpeg EXR dwa_uncompress
When decoding an OpenEXR file that uses DWAA or DWAB compression, there's an implicit assumption that all image channels have the same pixel type (and size), and that if there are four channels, the first four are "B", "G", "R" and "A". The channel parsing code can be found in decode_header. The buffer td->uncompressed_data is allocated in decode_block based on the xsize, ysize and computed current_channel_offset.
The function dwa_uncompress then assumes at [5] that if there are 4 channels, these are "B", "G", "R" and "A", and in the calculations at [6] and [7] that all channels are of the same type, which matches the type of the main color channels.
If we set the main color channels to a 4-byte type and add duplicate or unknown channels of the 2-byte EXR_HALF type, then the addition at [7] will increment the pointer by 4-bytes * xsize * nb_channels, which will exceed the allocated buffer.
We recommend upgrading to version 8.0 or beyond.
Weakness Type
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-2025-59733 has been classified to as a Memory Corruption vulnerability or weakness.
Products Associated with CVE-2025-59733
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Affected Versions
FFmpeg:- Version 9a32b863074ed4140141e0d3613905c6f1fe61c5 and below 8.0 is affected.
- Version 7.1.1 and below 8.0 is affected.
Exploit Probability
EPSS (Exploit Prediction Scoring System) scores estimate the probability that a vulnerability will be exploited in the wild within the next 30 days. The percentile shows you how this score compares to all other vulnerabilities.