# CVE-2026-34543: OpenEXR: Heap information disclosure in PXR24 decompression via unchecked decompressed size (undo_pxr24_impl)

Source: https://junglewise.ai/threats/cve-2026-34543-openexr-heap-information-disclosure-in-pxr24-decompression-via  
Publisher: Junglewise Threat Intelligence, https://junglewise.ai/threats  
Published: 2026-04-01  
License: CC BY 4.0 with a link back

CVE-2026-34543 · Severity: high · CVSS 7.5 · Published 2026-04-01

OpenEXR provides the specification and reference implementation of the EXR file format, an image storage format for the motion picture industry. From version 3.4.0 to before version 3.4.8, sensitive information from heap memory may be leaked through the decoded pixel data (information disclosure). This occurs under default settings; simply reading a malicious EXR file is sufficient to trigger the issue, without any user interaction. This issue has been patched in version 3.4.8.

Technologies: [Openexr](https://junglewise.ai/threats/technologies/openexr-openexr), [OpenEXR (PyPI)](https://junglewise.ai/threats/technologies/openexr). Vendors: [Openexr](https://junglewise.ai/threats/vendors/openexr), [PyPI](https://junglewise.ai/threats/vendors/pypi).

## Quick answers

**Is CVE-2026-34543 exploited in the wild?** No. Junglewise Threat Intelligence has no report of CVE-2026-34543 being exploited in the wild.

**How severe is CVE-2026-34543?** High severity, with a CVSS score of 7.5, published 1 April 2026.

**Which products and versions are affected?** OpenEXR (PyPI) >= 3.4.0, <= 3.4.7, ECOSYSTEM:introduced=3.2.0,fixed=3.4.8, ECOSYSTEM:introduced=3.4.0,fixed=3.4.8.

**Is there a fix for CVE-2026-34543?** Yes. OpenEXR (PyPI): upgrade to 3.4.8 or later. Junglewise finds every place you run it, drafts the upgrade and applies it once you approve.

**Am I affected by CVE-2026-34543?** Check whether you run Openexr or OpenEXR (PyPI) 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 3.4.8 or later

  ```sh
  pip install "OpenEXR>=3.4.8"
  ```


## Affected products

- Openexr
- OpenEXR (PyPI) >= 3.4.0, <= 3.4.7, ECOSYSTEM:introduced=3.2.0,fixed=3.4.8, ECOSYSTEM:introduced=3.4.0,fixed=3.4.8

## Identifiers

- CVE-2026-34543
- GHSA-vc68-257w-m432
- PYSEC-2026-2850

## Related threats

- [PYSEC-2026-2849 - OpenEXR has heap-buffer-overflow via signed integer underflow in ImfContextInit.cpp](https://junglewise.ai/threats/cve-2026-26981-openexr-has-heap-buffer-overflow-via-signed-integer-underflow-in)
- [PYSEC-2026-2844 - OpenEXR has use after free in PyObject_StealAttrString](https://junglewise.ai/threats/cve-2025-64183-openexr-has-use-after-free-in-pyobject-stealattrstring)
- [PYSEC-2026-2851 - OpenEXR has buffer overflow in PyOpenEXR_old's channels() and channel()](https://junglewise.ai/threats/cve-2025-64182-openexr-has-buffer-overflow-in-pyopenexr-old-s-channels-and)
- [PYSEC-2026-2843 - OpenEXR Makes Use of Uninitialized Memory](https://junglewise.ai/threats/cve-2025-64181-openexr-use-of-uninitialized-memory-in-generic-unpack)
- [PYSEC-2026-1748 - OpenEXR ScanLineProcess::run_fill NULL Pointer Write In "reduceMemory" Mode](https://junglewise.ai/threats/cve-2025-48073-openexr-scanlineprocess-run-fill-null-pointer-write-in)