CVE-2026-59186: Heap Overflow (CVSS 7.1)

Description

OpenEXR is the reference implementation and specification for the EXR image format, widely used in the motion picture industry. In versions before 3.2.11, 3.3.0 through 3.3.12, and 3.4.0 through 3.4.13, a crafted tiled EXR can trigger a heap out-of-bounds write on 32-bit/ILP32 builds when read through the public TiledRgbaInputFile RGBA API. The file uses a small 40x40 dataWindow but a 65537x65537 tile size. On ILP32, the Array2D<Rgba> tile-conversion buffer size calculation overflows, allocates a much smaller heap buffer, and tile decode writes past that allocation. This issue is fixed in versions 3.2.11, 3.3.13, and 3.4.14.

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CVSS v3.1 Score

7.1

HIGH

CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:L/A:H

EPSS — Exploit Prediction

0.0022

Probability of exploitation

0.13%

Percentile rank

EPSS estimates the probability that this vulnerability will be exploited in the wild within the next 30 days. A higher score means more likely to be exploited.

Weakness Type (CWE)

CWE-122 CWE-122

CWE-190 Integer Overflow

CWE-787 Out-of-bounds Write

References

Other References

https://github.com/AcademySoftwareFoundation/openexr/commit/71907b44ce9a1b05bf3934b8a7821752750731ab https://github.com/AcademySoftwareFoundation/openexr/commit/904141d3a1f86327ad1e2b93fc92ce2dd5881d34 https://github.com/AcademySoftwareFoundation/openexr/commit/b1a5887372772d79328f4eb42b7f86352a38170b https://github.com/AcademySoftwareFoundation/openexr/security/advisories/GHSA-f667-c4wm-c8gq https://github.com/AcademySoftwareFoundation/openexr/security/advisories/GHSA-f667-c4wm-c8gq

Frequently Asked Questions

What is CVE-2026-59186? +

OpenEXR is the reference implementation and specification for the EXR image format, widely used in the motion picture industry. In versions before 3.2.11, 3.3.0 through 3.3.12, and 3.4.0 through 3.4.13, a crafted tiled EXR can trigger a heap out-of-bounds write on 32-bit/ILP32 builds when read through the public TiledRgbaInputFile RGBA API. The file uses a small 40x40 dataWindow but a 65537x65537 tile size. On ILP32, the Array2D<Rgba> tile-conversion buffer size calculation overflows, allocates a much smaller heap buffer, and tile decode writes past that allocation. This issue is fixed in versions 3.2.11, 3.3.13, and 3.4.14. It has a CVSS v3.1 base score of 7.1 (HIGH).

How severe is CVE-2026-59186? +

CVE-2026-59186 has a CVSS v3.1 score of 7.1 out of 10, rated HIGH. This is a high-severity vulnerability that should be prioritized for patching. The EPSS score is 0.0022, placing it in the 0th percentile for exploitation probability.

How do I check if I'm vulnerable to CVE-2026-59186? +

You can use Secably's free Website Scanner to check your website for known vulnerabilities. For infrastructure scanning, use the Port Scanner to identify exposed services that may be affected. Check the vendor advisories linked above for specific patch and version information.

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CVE-2026-59186