Use of Uninitialized Variable Affecting openexr package, versions [3.3.0,3.3.6)[3.4.0,3.4.3)
Threat Intelligence
Snyk has a proof-of-concept or detailed explanation of how to exploit this vulnerability.
The probability is the direct output of the EPSS model, and conveys an overall sense of the threat of exploitation in the wild. The percentile measures the EPSS probability relative to all known EPSS scores. Note: This data is updated daily, relying on the latest available EPSS model version. Check out the EPSS documentation for more details.
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Test your applications- Snyk IDSNYK-PYTHON-OPENEXR-13877542
- published11 Nov 2025
- disclosed10 Nov 2025
- creditAldo Ristori
Introduced: 10 Nov 2025
NewCVE-2025-64181 (opens in a new tab)How to fix?
Upgrade OpenEXR to version 3.3.6, 3.4.3 or higher.
Overview
OpenEXR is a Python bindings for the OpenEXR image file format
Affected versions of this package are vulnerable to Use of Uninitialized Variable via the generic_unpack function. An attacker can trigger undefined behavior or cause a crash by providing specially crafted input that leads to the use of uninitialized memory.
PoC
The archive includes the test executable and a bug-triggering testcase. To see the bug, run the OSS-Fuzz helper script:
git clone https://github.com/google/oss-fuzz.git cd oss-fuzzpython3 infra/helper.py build_image openexr python3 infra/helper.py build_fuzzers --sanitizer=none openexr python3 infra/helper.py shell openexr
apt update && apt install -y valgrind ulimit -n 65535 valgrind --tool=memcheck --track-origins=yes /out/openexr_exrcheck_fuzzer /path/to/poc