CVE-2025-59733 Heap-buffer-overflow write in FFmpeg EXR dwa_uncompress
A heap-buffer-overflow in FFmpeg's EXR decoder allows attackers to execute arbitrary code or cause denial of service via crafted files.
- Exploited in the wild
- Not known
- Login needed
- Not needed
- Attackable
- Local or same network only
- Victim action needed
- A user has to click or open something
- Fix
- Available
What is CVE-2025-59733?
CVE-2025-59733 is a high-severity memory corruption vulnerability in FFmpeg, published on 6 Oct 2025. It can only be exploited from the same machine or local network, and only if a user opens a file or follows a link.
Official description
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: CWE-787
Which versions are affected by CVE-2025-59733?
How do I fix CVE-2025-59733?
Upgrade to a fixed version.
Upgrade to the fixed version. Memory-safe languages, compiler hardening and fuzzing prevent most new cases. More about Memory corruption.
Is CVE-2025-59733 being exploited?
There is no known exploitation of CVE-2025-59733 in the wild and no public exploit code.
Sources
Also known as DEBIAN-CVE-2025-59733, GHSA-hpfq-c235-5854, JLSEC-2026-646, MINI-xgfq-qpw9-rcvf.