CVE-2025-4516
Use-after-free in "unicode_escape" decoder with error handler
CVSS Score
0.0
EPSS Score
0.2%
EPSS Percentile
43th
There is an issue in CPython when using `bytes.decode("unicode_escape", error="ignore|replace")`. If you are not using the "unicode_escape" encoding or an error handler your usage is not affected. To work-around this issue you may stop using the error= handler and instead wrap the bytes.decode() call in a try-except catching the DecodeError.
| CWE | CWE-416 |
| Vendor | python software foundation |
| Product | cpython |
| Published | May 15, 2025 |
| Last Updated | Apr 21, 2026 |
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Affected Versions
Python Software Foundation / CPython
0 < 3.10.18 3.11.0 < 3.11.13 3.12.0 < 3.12.11 3.13.0 < 3.13.4 3.14.0a1 < 3.14.0b2
References
github.com: https://github.com/python/cpython/issues/133767 github.com: https://github.com/python/cpython/pull/129648 mail.python.org: https://mail.python.org/archives/list/[email protected]/thread/L75IPBBTSCYEF56I2M4KIW353BB3AY74/ github.com: https://github.com/python/cpython/commit/69b4387f78f413e8c47572a85b3478c47eba8142 github.com: https://github.com/python/cpython/commit/9f69a58623bd01349a18ba0c7a9cb1dad6a51e8e github.com: https://github.com/python/cpython/commit/4398b788ffc1f954a2c552da285477d42a571292 github.com: https://github.com/python/cpython/commit/6279eb8c076d89d3739a6edb393e43c7929b429d github.com: https://github.com/python/cpython/commit/73b3040f592436385007918887b7e2132aa8431f github.com: https://github.com/python/cpython/commit/8d35fd1b34935221aff23a1ab69a429dd156be77 github.com: https://github.com/python/cpython/commit/ab9893c40609935e0d40a6d2a7307ea51aec598b openwall.com: http://www.openwall.com/lists/oss-security/2025/05/16/4 openwall.com: http://www.openwall.com/lists/oss-security/2025/05/19/1