The vulnerability in openexr arises from an integer overflow in the accumulation of per-pixel totals in a vector<unsigned int> total_sizes, which wraps modulo 2^32 for large attacker-controlled counts. This results in an incorrect overall_sample_count used to resize sample buffers, causing undersized buffers. Subsequent write operations in the core unpack function overrun these buffers, leading to an out-of-bounds write (CWE-787). This can be exploited to achieve arbitrary code execution. The vulnerability is addressed in openexr versions 3.2.6, 3.3.8, and 3.4.6. Red Hat has issued security advisories and patches for affected distributions, including Red Hat Enterprise Linux 10.0 Extended Update Support.

Successful exploitation of this vulnerability can lead to arbitrary code execution due to out-of-bounds writes in the openexr library when processing crafted EXR image files. This poses a significant risk to systems using vulnerable versions of openexr, potentially allowing attackers to execute code with the privileges of the user running the vulnerable application.

Fixes for this vulnerability are available in openexr versions 3.2.6, 3.3.8, and 3.4.6. Users and administrators should upgrade to one of these fixed versions to remediate the issue. Red Hat has released security advisories and updated packages for affected Red Hat Enterprise Linux versions, which should be applied promptly. Patch status is confirmed by vendor advisories. No additional mitigations are indicated beyond applying these official fixes.