Use-after-free in Python - CVE-2025-4516
Published: June 28, 2025
Vulnerability identifier: #VU112030
CSH Severity: Medium
CVSS v4.0: CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:L/SC:N/SI:N/SA:N/E:U/U:Green
CVE-ID: CVE-2025-4516
CWE-ID: CWE-416
Exploitation vector: Remote access
Exploit availability:
No public exploit available
Vendor: Python.org
Affected software:
Python
Python
Detailed vulnerability description
The vulnerability allows a remote attacker to perform a denial of service (DoS) attack.
The vulnerability exists due to a use-after-free error when using the bytes.decode("unicode_escape", error="ignore|replace") function call. A remote attacker can pass a specially crafted input to the application and perform a denial of service (DoS) attack.
How to mitigate CVE-2025-4516
Install updates from vendor's website.
Sources
- http://www.openwall.com/lists/oss-security/2025/05/16/4
- http://www.openwall.com/lists/oss-security/2025/05/19/1
- https://github.com/python/cpython/commit/4398b788ffc1f954a2c552da285477d42a571292
- https://github.com/python/cpython/commit/6279eb8c076d89d3739a6edb393e43c7929b429d
- https://github.com/python/cpython/commit/69b4387f78f413e8c47572a85b3478c47eba8142
- https://github.com/python/cpython/commit/73b3040f592436385007918887b7e2132aa8431f
- https://github.com/python/cpython/commit/8d35fd1b34935221aff23a1ab69a429dd156be77
- https://github.com/python/cpython/commit/9f69a58623bd01349a18ba0c7a9cb1dad6a51e8e
- https://github.com/python/cpython/commit/ab9893c40609935e0d40a6d2a7307ea51aec598b
- https://github.com/python/cpython/issues/133767
- https://github.com/python/cpython/pull/129648
- https://mail.python.org/archives/list/security-announce@python.org/thread/L75IPBBTSCYEF56I2M4KIW353BB3AY74/