Vulnerability Description
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.
Related Weaknesses (CWE)
References
- https://github.com/python/cpython/commit/4398b788ffc1f954a2c552da285477d42a57129
- https://github.com/python/cpython/commit/6279eb8c076d89d3739a6edb393e43c7929b429
- https://github.com/python/cpython/commit/69b4387f78f413e8c47572a85b3478c47eba814
- https://github.com/python/cpython/commit/73b3040f592436385007918887b7e2132aa8431
- https://github.com/python/cpython/commit/8d35fd1b34935221aff23a1ab69a429dd156be7
- https://github.com/python/cpython/commit/9f69a58623bd01349a18ba0c7a9cb1dad6a51e8
- https://github.com/python/cpython/commit/ab9893c40609935e0d40a6d2a7307ea51aec598
- https://github.com/python/cpython/issues/133767
- https://github.com/python/cpython/pull/129648
- https://mail.python.org/archives/list/[email protected]/thread/L75IPB
- http://www.openwall.com/lists/oss-security/2025/05/16/4
- http://www.openwall.com/lists/oss-security/2025/05/19/1
FAQ
What is CVE-2025-4516?
CVE-2025-4516 is a documented vulnerability. 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 ...
How severe is CVE-2025-4516?
CVSS scoring is not yet available for CVE-2025-4516. Check NVD for updates.
Is there a patch for CVE-2025-4516?
Check the references section above for vendor advisories and patch information. Review vendor security bulletins for remediation guidance.