CVE-2026-55059 OpenEXR: OpenEXRUtil SampleCountChannel row setter heap has an out-of-bounds write vulnerability
A heap out-of-bounds write in OpenEXR allows attackers to cause crashes or potentially execute code via crafted deep image 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-2026-55059?
CVE-2026-55059 is a medium-severity memory corruption vulnerability in AcademySoftwareFoundation openexr, published on 25 Aug 2026. 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
OpenEXR is the reference implementation and specification for the EXR image format, widely used in the motion picture industry. Versions prior to 3.2.10, 3.3.12 and 3.4.13 contain a heap out-of-bounds write in Imf_4_0::SampleCountChannel::set(int r, unsigned int newNumSamples[]). The row-based sample-count setter computes the target Y coordinate with dataWindow.min.x instead of dataWindow.min.y. For a valid deep image data window where min.x != min.y, a valid row index can be translated into an invalid Y coordinate, causing writes before the allocated _numSamples buffer. The vulnerability is reachable through the public OpenEXRUtil DeepImage API and can lead to heap corruption and process crashes. This issue has been fixed in versions 3.2.10, 3.3.12 and 3.4.13.
Weakness: CWE-787
Which versions are affected by CVE-2026-55059?
How do I fix CVE-2026-55059?
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-2026-55059 being exploited?
It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-55059 exists.
Sources
Also known as AZL-97626, BELL-CVE-2026-55059, CLSA-2026-1792587918, DEBIAN-CVE-2026-55059, ECHO-460b-2c90-9266, GHSA-54cp-3rq6-7mq8 and 2 more.