CVE-2026-34544: PYSEC-2026-2847 - OpenEXR: integer overflow to OOB write in uncompress_b44_impl()

CVE-2026-34544 · Severity: high · CVSS 7.3 · 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, a crafted B44 or B44A EXR file can cause an out-of-bounds write in any application that decodes it via exr_decoding_run(). Consequences range from immediate crash (most likely) to corruption of adjacent heap allocations (layout-dependent). This issue has been patched in version 3.4.8.

Technologies: Openexr, OpenEXR (PyPI). Vendors: Openexr, PyPI.

Quick answers

Is CVE-2026-34544 exploited in the wild?
No. Junglewise Threat Intelligence has no report of CVE-2026-34544 being exploited in the wild.
How severe is CVE-2026-34544?
High severity, with a CVSS score of 7.3, published 1 April 2026.
Which products and versions are affected?
OpenEXR (PyPI) ECOSYSTEM:introduced=3.2.0,fixed=3.4.8, ECOSYSTEM:introduced=3.4.0,fixed=3.4.8.
Is there a fix for CVE-2026-34544?
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-2026-34544?
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
    pip install "OpenEXR>=3.4.8"

Affected products

  • Openexr
  • OpenEXR (PyPI) ECOSYSTEM:introduced=3.2.0,fixed=3.4.8, ECOSYSTEM:introduced=3.4.0,fixed=3.4.8

Identifiers

  • CVE-2026-34544
  • GHSA-h762-rhv3-h25v
  • PYSEC-2026-2847

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