# CVE-2026-59156: OpenImageIO stack overflow in FITS header parsing

Source: https://junglewise.ai/threats/cve-2026-59156-openimageio-is-a-toolset-for-reading-writing-and-manipulating  
Publisher: Junglewise Threat Intelligence, https://junglewise.ai/threats  
Published: 2026-09-18. Updated: 2026-09-26  
License: CC BY 4.0 with a link back

CVE-2026-59156 · Severity: medium · CVSS 6.5 · Published 2026-09-18

OpenImageIO is a toolset for reading and manipulating image files used in VFX and animation production. A crafted FITS image file with excessive header blocks can trigger a stack overflow in the parsing code, causing the application to crash and resulting in denial of service for any workflow processing untrusted FITS files.

Technologies: [Academy Software Foundation OpenImageIO](https://junglewise.ai/threats/technologies/openimageio). Vendors: [Academy Software Foundation](https://junglewise.ai/threats/vendors/academy-software-foundation).

## Quick answers

**Is CVE-2026-59156 exploited in the wild?** No. Junglewise Threat Intelligence has no report of CVE-2026-59156 being exploited in the wild.

**How severe is CVE-2026-59156?** Medium severity, with a CVSS score of 6.5, published 18 September 2026.

**Which products and versions are affected?** Academy Software Foundation OpenImageIO before 3.0.20.0, before 3.1.15.0, before 3.2.0.3-beta1.

**Is there a fix for CVE-2026-59156?** A patch was published on 2026-06-20: Fix committed to main branch Junglewise finds every place you run it, drafts the upgrade and applies it once you approve.

**How is CVE-2026-59156 attacked?** It is attacked over the network, in a software library.

**Am I affected by CVE-2026-59156?** Check whether you run Academy Software Foundation OpenImageIO at an affected version. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.

## Technical details

The vulnerability is a stack overflow caused by unbounded recursion in FitsInput::read_fits_header() when parsing FITS files with many consecutive 2880-byte header blocks lacking the mandatory END keyword. An attacker can supply a malicious FITS file that exhausts the application stack through recursive parsing calls. The fix converts the recursive implementation to an iterative loop with a maximum limit of 10,000 header blocks.

## Affected products

- Academy Software Foundation OpenImageIO before 3.0.20.0, before 3.1.15.0, before 3.2.0.3-beta1

## Timeline

- 2026-09-18: disclosed
- 2026-06-20: patched: Fix committed to main branch

## References

- [https://github.com/AcademySoftwareFoundation/OpenImageIO/commit/b0de7d40d06eb4abc7ef14c1321a1a2a976d8c1c](https://github.com/AcademySoftwareFoundation/OpenImageIO/commit/b0de7d40d06eb4abc7ef14c1321a1a2a976d8c1c)
- [https://github.com/AcademySoftwareFoundation/OpenImageIO/pull/5248](https://github.com/AcademySoftwareFoundation/OpenImageIO/pull/5248)

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