# CVE-2026-34589: OpenEXR heap out-of-bounds write in DWA lossy decoder

Source: https://junglewise.ai/threats/cve-2026-34589-openexr-heap-out-of-bounds-write-in-dwa-lossy-decoder  
Publisher: Junglewise Threat Intelligence, https://junglewise.ai/threats  
Published: 2026-04-06. Updated: 2026-06-30  
License: CC BY 4.0 with a link back

CVE-2026-34589 · Severity: medium · CVSS 5 · Published 2026-04-06

OpenEXR is a widely used professional-grade image format for the motion picture and visual effects industry. A vulnerability in its image decoding component allows a specially crafted image file to cause a memory error when opened. This could lead to a program crash or potentially allow an attacker to execute unauthorized code on the user's system, impacting data confidentiality and system availability.

Technologies: [OpenEXR (PyPI)](https://junglewise.ai/threats/technologies/openexr), [Red Hat Enterprise Linux 6](https://junglewise.ai/threats/technologies/enterprise-linux-6), [Red Hat Enterprise Linux 7](https://junglewise.ai/threats/technologies/enterprise-linux-7). Vendors: [PyPI](https://junglewise.ai/threats/vendors/pypi), [Red Hat](https://junglewise.ai/threats/vendors/red-hat).

## Quick answers

**Is CVE-2026-34589 exploited in the wild?** No. Junglewise Threat Intelligence has no report of CVE-2026-34589 being exploited in the wild.

**How severe is CVE-2026-34589?** Medium severity, with a CVSS score of 5, published 6 April 2026.

**Which products and versions are affected?** OpenEXR (PyPI) ECOSYSTEM:introduced=3.2.0,fixed=3.2.7, ECOSYSTEM:introduced=3.2.0,fixed=3.2.7,introduced=3.3.0,fixed=3.3.9,introduced=3.4.0,fixed=3.4.9; Red Hat Enterprise Linux 6 affected; Red Hat Enterprise Linux 7 affected.

**Is there a fix for CVE-2026-34589?** Yes. OpenEXR (PyPI): upgrade to 3.2.7, 3.4.9 or later. Junglewise finds every place you run it, drafts the upgrade and applies it once you approve.

**How is CVE-2026-34589 attacked?** It is attacked with local access, in a software library.

**Am I affected by CVE-2026-34589?** Check whether you run OpenEXR (PyPI), Red Hat Enterprise Linux 6 or Red Hat Enterprise Linux 7 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.

## How to fix

- OpenEXR (PyPI): upgrade to 3.2.7, 3.4.9 or later

  ```sh
  pip install "OpenEXR>=3.4.9"
  ```


## Technical details

An integer overflow vulnerability exists in the DWA lossy decoder of OpenEXR within 'src/lib/OpenEXRCore/internal_dwa_decoder.h'. The issue stems from using signed 32-bit arithmetic to calculate temporary per-component block pointers (numBlocksX * 64). When processing an image with a sufficiently large width, this calculation overflows, causing the resulting pointer to wrap and point outside the allocated 'rowBlock' backing store. Subsequent write operations in 'LossyDctDecoder_execute' then perform out-of-bounds writes. This is reachable via the public decoder path and can be triggered by a crafted scanline DWAA file. Patches are available in versions 3.2.7, 3.3.9, and 3.4.9.

## Affected products

- AcademySoftwareFoundation OpenEXR >= 3.2.0, < 3.2.7; >= 3.3.0, < 3.3.9; >= 3.4.0, < 3.4.9
- Red Hat Red Hat Enterprise Linux 6 affected
- Red Hat Red Hat Enterprise Linux 7 affected

## Identifiers

- CVE-2026-34589
- GHSA-p8xc-w3q4-h64x
- PYSEC-2026-2848

## Timeline

- 2026-04-03: patched: Versions 3.2.7, 3.3.9, and 3.4.9 released.
- 2026-04-05: advisory: GitHub Security Advisory GHSA-p8xc-w3q4-h64x published.
- 2026-04-06: disclosed: CVE-2026-34589 published.

## References

- [https://github.com/AcademySoftwareFoundation/openexr/releases/tag/v3.2.7](https://github.com/AcademySoftwareFoundation/openexr/releases/tag/v3.2.7)
- [https://github.com/AcademySoftwareFoundation/openexr/releases/tag/v3.3.9](https://github.com/AcademySoftwareFoundation/openexr/releases/tag/v3.3.9)
- [https://github.com/AcademySoftwareFoundation/openexr/releases/tag/v3.4.9](https://github.com/AcademySoftwareFoundation/openexr/releases/tag/v3.4.9)
- [https://github.com/AcademySoftwareFoundation/openexr/security/advisories/GHSA-p8xc-w3q4-h64x](https://github.com/AcademySoftwareFoundation/openexr/security/advisories/GHSA-p8xc-w3q4-h64x)
- [https://access.redhat.com/security/cve/CVE-2026-34589](https://access.redhat.com/security/cve/CVE-2026-34589)
- [https://bugzilla.redhat.com/show_bug.cgi?id=2455411](https://bugzilla.redhat.com/show_bug.cgi?id=2455411)
- [https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-34589.json](https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-34589.json)

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