CVE-2025-64183
OpenEXR has use after free in PyObject_StealAttrString
EPSS Exploitation Probability
EPSS (Exploit Prediction Scoring System) is a daily probability model maintained by FIRST.org. It estimates the likelihood a CVE will be exploited in production environments within the next 30 days, derived from real-world threat intelligence signals.
Blast Radius
openexr🐍openexr🐍openexrReal-time download stats are indexed for npm and PyPI packages. This vulnerability affects PyPI packages — download data is not available via public APIs for these ecosystems.
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.
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| 🐍PyPI | openexr | ≥ 3.2.0&&< 3.2.5 | 3.2.5 |
| 🐍PyPI | openexr | ≥ 3.3.0&&< 3.3.6 | 3.3.6 |
| 🐍PyPI | openexr | ≥ 3.4.0&&< 3.4.3 | 3.4.3 |
Detection & mitigation playbook
Open-source dependencyDetect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for openexr. O3's reachability analysis confirms whether the vulnerable code path is actually invoked in your application, so you act on real exposure instead of every transitive match.
Fix
Update openexr to 3.2.5 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2025-64183 is resolved across your whole dependency graph.
Workarounds
If you can't upgrade right away: gate or disable the affected feature, validate untrusted input at the boundary, and avoid passing attacker-controlled data into the vulnerable path. O3's runtime protection blocks exploitation in production as an interim safeguard until the upgrade lands.
How O3 protects you
O3 pinpoints whether CVE-2025-64183 is reachable in your code and exactly where to fix it, then blocks exploitation in production at runtime until the patched version is deployed.
Tailored to CVE-2025-64183. Runtime protection reduces exposure until a permanent patch is applied and verified — it complements patching, it doesn't replace it.
Frequently Asked Questions
Is CVE-2025-64183 in your dependencies?
O3 detects CVE-2025-64183 across PyPI dependencies and uses function-level reachability to confirm whether the vulnerable code path is actually reachable — not just present. No false positives.