CVE-2025-4516mediumCWE-416

CVE-2025-4516: medium-severity vulnerability in Python Software Foundation CPython

Use-after-free in "unicode_escape" decoder with error handler

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13Vexday Risk Score

No sign of exploitation. No public exploitation artifact known so far.

ssvc Trackcvss 5.9epss 0.2%
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.
CVSS:4.0/AV:L/AC:H/AT:P/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N
Affected products
Python Software Foundation · CPython
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