Vulnerability · Published May 15, 2025 · Assigned by PSF
CVE-2025-4516Use-after-free in "unicode_escape" decoder with error handler
Medium 5.9
In plain English
A medium-severity use-after-free in CPython from Python Software Foundation. There are no confirmed reports of exploitation so far. The chance it is exploited in the next 30 days is estimated at 0.2% (higher than 13% of all known vulnerabilities). Fixed versions are available - upgrade the affected package.
Severity (CVSS 4.0)5.9Medium
Exploit odds (30 days)0.2%top 86.7% of all CVEs
Exploited in the wildNo reportsCISA SSVC: none
Attack toolingNoneno public tooling known
Official 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.
Affected packages & fixed versions
| Ecosystem | Package | Fixed in | Advisory |
|---|---|---|---|
| AlmaLinux:8 | python39 | 3.9.25-2.module_el8.10.0+4083+53cad1fb | ALSA-2025:23530 |
| AlmaLinux:8 | python39-Cython | 0.29.21-5.module_el8.6.0+2780+a40f65e1 | ALSA-2025:23530 |
| AlmaLinux:8 | python39-Cython | 0.29.21-5.module_el8.6.0+3248+c431e88c | ALSA-2025:23530 |
| AlmaLinux:8 | python39-PyMySQL | 0.10.1-2.module_el8.6.0+2780+a40f65e1 | ALSA-2025:23530 |
| AlmaLinux:8 | python39-attrs | 20.3.0-2.module_el8.6.0+2780+a40f65e1 | ALSA-2025:23530 |
| AlmaLinux:8 | python39-cffi | 1.14.3-2.module_el8.6.0+2780+a40f65e1 | ALSA-2025:23530 |
| AlmaLinux:8 | python39-cffi | 1.14.3-2.module_el8.6.0+3248+c431e88c | ALSA-2025:23530 |
| AlmaLinux:8 | python39-chardet | 3.0.4-19.module_el8.6.0+2780+a40f65e1 | ALSA-2025:23530 |
| AlmaLinux:8 | python39-cryptography | 3.3.1-3.module_el8.10.0+3765+2f9a457d | ALSA-2025:23530 |
| AlmaLinux:8 | python39-debug | 3.9.25-2.module_el8.10.0+4083+53cad1fb | ALSA-2025:23530 |
| AlmaLinux:8 | python39-devel | 3.9.25-2.module_el8.10.0+4083+53cad1fb | ALSA-2025:23530 |
| AlmaLinux:8 | python39-idle | 3.9.25-2.module_el8.10.0+4083+53cad1fb | ALSA-2025:23530 |
| AlmaLinux:8 | python39-idna | 2.10-4.module_el8.10.0+3849+a48d89aa | ALSA-2025:23530 |
| AlmaLinux:8 | python39-iniconfig | 1.1.1-2.module_el8.6.0+2780+a40f65e1 | ALSA-2025:23530 |
| AlmaLinux:8 | python39-libs | 3.9.25-2.module_el8.10.0+4083+53cad1fb | ALSA-2025:23530 |
| AlmaLinux:8 | python39-lxml | 4.6.5-1.module_el8.6.0+2780+a40f65e1 | ALSA-2025:23530 |
| AlmaLinux:8 | python39-lxml | 4.6.5-1.module_el8.6.0+3248+c431e88c | ALSA-2025:23530 |
| AlmaLinux:8 | python39-mod_wsgi | 4.7.1-7.module_el8.10.0+3989+a618fe15.1 | ALSA-2025:23530 |
| AlmaLinux:8 | python39-more-itertools | 8.5.0-2.module_el8.6.0+2780+a40f65e1 | ALSA-2025:23530 |
| AlmaLinux:8 | python39-numpy | 1.19.4-3.module_el8.6.0+2780+a40f65e1 | ALSA-2025:23530 |
| AlmaLinux:8 | python39-numpy | 1.19.4-3.module_el8.6.0+3248+c431e88c | ALSA-2025:23530 |
| AlmaLinux:8 | python39-numpy-doc | 1.19.4-3.module_el8.6.0+2780+a40f65e1 | ALSA-2025:23530 |
| AlmaLinux:8 | python39-numpy-f2py | 1.19.4-3.module_el8.6.0+2780+a40f65e1 | ALSA-2025:23530 |
| AlmaLinux:8 | python39-numpy-f2py | 1.19.4-3.module_el8.6.0+3248+c431e88c | ALSA-2025:23530 |
| AlmaLinux:8 | python39-packaging | 20.4-4.module_el8.6.0+2780+a40f65e1 | ALSA-2025:23530 |
| AlmaLinux:8 | python39-pip | 20.2.4-9.module_el8.10.0+3765+2f9a457d | ALSA-2025:23530 |
| AlmaLinux:8 | python39-pip-wheel | 20.2.4-9.module_el8.10.0+3765+2f9a457d | ALSA-2025:23530 |
| AlmaLinux:8 | python39-pluggy | 0.13.1-3.module_el8.6.0+2780+a40f65e1 | ALSA-2025:23530 |
| AlmaLinux:8 | python39-ply | 3.11-10.module_el8.6.0+2780+a40f65e1 | ALSA-2025:23530 |
| AlmaLinux:8 | python39-psutil | 5.8.0-4.module_el8.6.0+2780+a40f65e1 | ALSA-2025:23530 |
| AlmaLinux:8 | python39-psutil | 5.8.0-4.module_el8.6.0+3248+c431e88c | ALSA-2025:23530 |
| AlmaLinux:8 | python39-psycopg2 | 2.8.6-3.module_el8.10.0+3765+2f9a457d | ALSA-2025:23530 |
| AlmaLinux:8 | python39-psycopg2-doc | 2.8.6-3.module_el8.10.0+3765+2f9a457d | ALSA-2025:23530 |
| AlmaLinux:8 | python39-psycopg2-tests | 2.8.6-3.module_el8.10.0+3765+2f9a457d | ALSA-2025:23530 |
| AlmaLinux:8 | python39-py | 1.10.0-1.module_el8.6.0+2780+a40f65e1 | ALSA-2025:23530 |
| AlmaLinux:8 | python39-pybind11 | 2.7.1-1.module_el8.6.0+2780+a40f65e1 | ALSA-2025:23530 |
| AlmaLinux:8 | python39-pybind11 | 2.7.1-1.module_el8.6.0+3248+c431e88c | ALSA-2025:23530 |
| AlmaLinux:8 | python39-pybind11-devel | 2.7.1-1.module_el8.6.0+2780+a40f65e1 | ALSA-2025:23530 |
| AlmaLinux:8 | python39-pybind11-devel | 2.7.1-1.module_el8.6.0+3248+c431e88c | ALSA-2025:23530 |
| AlmaLinux:8 | python39-pycparser | 2.20-3.module_el8.6.0+2780+a40f65e1 | ALSA-2025:23530 |
| AlmaLinux:8 | python39-pyparsing | 2.4.7-5.module_el8.6.0+2780+a40f65e1 | ALSA-2025:23530 |
| AlmaLinux:8 | python39-pysocks | 1.7.1-4.module_el8.6.0+2780+a40f65e1 | ALSA-2025:23530 |
| AlmaLinux:8 | python39-pytest | 6.0.2-2.module_el8.6.0+2780+a40f65e1 | ALSA-2025:23530 |
| AlmaLinux:8 | python39-pyyaml | 5.4.1-1.module_el8.6.0+2780+a40f65e1 | ALSA-2025:23530 |
| AlmaLinux:8 | python39-pyyaml | 5.4.1-1.module_el8.6.0+3248+c431e88c | ALSA-2025:23530 |
| AlmaLinux:8 | python39-requests | 2.25.0-3.module_el8.9.0+3634+fb2a896c | ALSA-2025:23530 |
| AlmaLinux:8 | python39-rpm-macros | 3.9.25-2.module_el8.10.0+4083+53cad1fb | ALSA-2025:23530 |
| AlmaLinux:8 | python39-scipy | 1.5.4-5.module_el8.9.0+3634+fb2a896c | ALSA-2025:23530 |
| AlmaLinux:8 | python39-setuptools | 50.3.2-7.module_el8.10.0+4040+9207bbc0 | ALSA-2025:23530 |
| AlmaLinux:8 | python39-setuptools-wheel | 50.3.2-7.module_el8.10.0+4040+9207bbc0 | ALSA-2025:23530 |
| AlmaLinux:8 | python39-six | 1.15.0-3.module_el8.6.0+2780+a40f65e1 | ALSA-2025:23530 |
| AlmaLinux:8 | python39-test | 3.9.25-2.module_el8.10.0+4083+53cad1fb | ALSA-2025:23530 |
| AlmaLinux:8 | python39-tkinter | 3.9.25-2.module_el8.10.0+4083+53cad1fb | ALSA-2025:23530 |
| AlmaLinux:8 | python39-toml | 0.10.1-5.module_el8.6.0+2780+a40f65e1 | ALSA-2025:23530 |
| AlmaLinux:8 | python39-urllib3 | 1.25.10-5.module_el8.10.0+3765+2f9a457d | ALSA-2025:23530 |
| AlmaLinux:8 | python39-wcwidth | 0.2.5-3.module_el8.6.0+2780+a40f65e1 | ALSA-2025:23530 |
| AlmaLinux:8 | python39-wheel | 1:0.35.1-4.module_el8.6.0+2780+a40f65e1 | ALSA-2025:23530 |
| AlmaLinux:8 | python39-wheel-wheel | 1:0.35.1-4.module_el8.6.0+2780+a40f65e1 | ALSA-2025:23530 |
| Alpine:v3.20 | python3 | 3.12.10-r1 | ALPINE-CVE-2025-4516 |
| Alpine:v3.21 | python3 | 3.12.10-r1 | ALPINE-CVE-2025-4516 |
| Alpine:v3.22 | python3 | 3.12.10-r1 | ALPINE-CVE-2025-4516 |
| Alpine:v3.23 | python3 | 3.12.10-r1 | ALPINE-CVE-2025-4516 |
| Alpine:v3.24 | python3 | 3.12.10-r1 | ALPINE-CVE-2025-4516 |
| Debian:12 | python3.11 | 3.11.2-6+deb12u7 | DEBIAN-CVE-2025-4516 |
| Debian:13 | python3.13 | 3.13.3-4 | DEBIAN-CVE-2025-4516 |
| Rocky Linux:8 | Cython | 0:0.29.21-5.module+el8.10.0+1860+afcc1c71 | RLSA-2025:23530 |
| Rocky Linux:8 | Cython | 0:0.29.21-5.module+el8.10.0+1582+bc278001 | RLSA-2025:23530 |
| Rocky Linux:8 | PyYAML | 0:5.4.1-1.module+el8.10.0+1860+afcc1c71 | RLSA-2025:23530 |
| Rocky Linux:8 | PyYAML | 0:5.4.1-1.module+el8.9.0+1418+f0d66789 | RLSA-2025:23530 |
| Rocky Linux:8 | PyYAML | 0:5.4.1-1.module+el8.10.0+1582+bc278001 | RLSA-2025:23530 |
| Rocky Linux:8 | mod_wsgi | 0:4.7.1-7.module+el8.10.0+1860+afcc1c71 | RLSA-2025:23530 |
| Rocky Linux:8 | mod_wsgi | 0:4.7.1-7.module+el8.10.0+1582+bc278001 | RLSA-2025:23530 |
| Rocky Linux:8 | mod_wsgi | 0:4.7.1-7.module+el8.10.0+1978+d4f111ba.1 | RLSA-2025:23530 |
| Rocky Linux:8 | numpy | 0:1.19.4-3.module+el8.10.0+1860+afcc1c71 | RLSA-2025:23530 |
| Rocky Linux:8 | numpy | 0:1.19.4-3.module+el8.10.0+1582+bc278001 | RLSA-2025:23530 |
| Rocky Linux:8 | pybind11 | 0:2.7.1-1.module+el8.9.0+1357+a3b80af7 | RLSA-2025:23530 |
| Rocky Linux:8 | pytest | 0:6.0.2-2.module+el8.10.0+1860+afcc1c71 | RLSA-2025:23530 |
| Rocky Linux:8 | pytest | 0:6.0.2-2.module+el8.10.0+1582+bc278001 | RLSA-2025:23530 |
| Rocky Linux:8 | python-PyMySQL | 0:0.10.1-2.module+el8.10.0+1592+61442852 | RLSA-2025:23530 |
| Rocky Linux:8 | python-PyMySQL | 0:0.10.1-2.module+el8.10.0+1910+234ad790 | RLSA-2025:23530 |
| Rocky Linux:8 | python-PyMySQL | 0:0.10.1-2.module+el8.10.0+1582+bc278001 | RLSA-2025:23530 |
| Rocky Linux:8 | python-PyMySQL | 0:0.10.1-2.module+el8.10.0+1860+afcc1c71 | RLSA-2025:23530 |
| Rocky Linux:8 | python-attrs | 0:20.3.0-2.module+el8.10.0+1860+afcc1c71 | RLSA-2025:23530 |
| Rocky Linux:8 | python-attrs | 0:20.3.0-2.module+el8.10.0+1582+bc278001 | RLSA-2025:23530 |
| Rocky Linux:8 | python-cffi | 0:1.14.3-2.module+el8.10.0+1860+afcc1c71 | RLSA-2025:23530 |
| Rocky Linux:8 | python-cffi | 0:1.14.3-2.module+el8.10.0+1582+bc278001 | RLSA-2025:23530 |
| Rocky Linux:8 | python-chardet | 0:3.0.4-19.module+el8.10.0+1582+bc278001 | RLSA-2025:23530 |
| Rocky Linux:8 | python-chardet | 0:3.0.4-19.module+el8.10.0+1860+afcc1c71 | RLSA-2025:23530 |
| Rocky Linux:8 | python-chardet | 0:3.0.4-19.module+el8.9.0+1418+f0d66789 | RLSA-2025:23530 |
| Rocky Linux:8 | python-cryptography | 0:3.3.1-3.module+el8.10.0+1697+7e517775 | RLSA-2025:23530 |
| Rocky Linux:8 | python-cryptography | 0:3.3.1-3.module+el8.10.0+1860+afcc1c71 | RLSA-2025:23530 |
| Rocky Linux:8 | python-idna | 0:2.10-4.module+el8.10.0+1809+41195054 | RLSA-2025:23530 |
| Rocky Linux:8 | python-idna | 0:2.10-4.module+el8.10.0+1860+afcc1c71 | RLSA-2025:23530 |
| Rocky Linux:8 | python-iniconfig | 0:1.1.1-2.module+el8.9.0+1332+dd574197 | RLSA-2025:23530 |
| Rocky Linux:8 | python-lxml | 0:4.6.5-1.module+el8.10.0+1582+bc278001 | RLSA-2025:23530 |
| Rocky Linux:8 | python-more-itertools | 0:8.5.0-2.module+el8.10.0+1860+afcc1c71 | RLSA-2025:23530 |
| Rocky Linux:8 | python-more-itertools | 0:8.5.0-2.module+el8.10.0+1582+bc278001 | RLSA-2025:23530 |
| Rocky Linux:8 | python-packaging | 0:20.4-4.module+el8.10.0+1582+bc278001 | RLSA-2025:23530 |
| Rocky Linux:8 | python-packaging | 0:20.4-4.module+el8.10.0+1860+afcc1c71 | RLSA-2025:23530 |
| Rocky Linux:8 | python-pluggy | 0:0.13.1-3.module+el8.10.0+1582+bc278001 | RLSA-2025:23530 |
| Rocky Linux:8 | python-pluggy | 0:0.13.1-3.module+el8.10.0+1860+afcc1c71 | RLSA-2025:23530 |
| Rocky Linux:8 | python-ply | 0:3.11-10.module+el8.10.0+1860+afcc1c71 | RLSA-2025:23530 |
| Rocky Linux:8 | python-ply | 0:3.11-10.module+el8.9.0+1418+f0d66789 | RLSA-2025:23530 |
| Rocky Linux:8 | python-ply | 0:3.11-10.module+el8.10.0+1582+bc278001 | RLSA-2025:23530 |
| Rocky Linux:8 | python-psutil | 0:5.8.0-4.module+el8.9.0+1357+a3b80af7 | RLSA-2025:23530 |
| Rocky Linux:8 | python-psycopg2 | 0:2.8.6-3.module+el8.10.0+1660+b5b6f004 | RLSA-2025:23530 |
| Rocky Linux:8 | python-psycopg2 | 0:2.8.6-3.module+el8.10.0+1860+afcc1c71 | RLSA-2025:23530 |
| Rocky Linux:8 | python-py | 0:1.10.0-1.module+el8.10.0+1860+afcc1c71 | RLSA-2025:23530 |
| Rocky Linux:8 | python-py | 0:1.10.0-1.module+el8.10.0+1582+bc278001 | RLSA-2025:23530 |
| Rocky Linux:8 | python-pycparser | 0:2.20-3.module+el8.10.0+1582+bc278001 | RLSA-2025:23530 |
| Rocky Linux:8 | python-pycparser | 0:2.20-3.module+el8.10.0+1860+afcc1c71 | RLSA-2025:23530 |
| Rocky Linux:8 | python-pysocks | 0:1.7.1-4.module+el8.10.0+1860+afcc1c71 | RLSA-2025:23530 |
| Rocky Linux:8 | python-pysocks | 0:1.7.1-4.module+el8.9.0+1418+f0d66789 | RLSA-2025:23530 |
| Rocky Linux:8 | python-pysocks | 0:1.7.1-4.module+el8.10.0+1582+bc278001 | RLSA-2025:23530 |
| Rocky Linux:8 | python-requests | 0:2.25.0-3.module+el8.10.0+1860+afcc1c71 | RLSA-2025:23530 |
| Rocky Linux:8 | python-requests | 0:2.25.0-3.module+el8.10.0+1582+bc278001 | RLSA-2025:23530 |
| Rocky Linux:8 | python-toml | 0:0.10.1-5.module+el8.9.0+1332+dd574197 | RLSA-2025:23530 |
| Rocky Linux:8 | python-urllib3 | 0:1.25.10-5.module+el8.10.0+1860+afcc1c71 | RLSA-2025:23530 |
| Rocky Linux:8 | python-urllib3 | 0:1.25.10-5.module+el8.10.0+1545+03246da9 | RLSA-2025:23530 |
| Rocky Linux:8 | python-wcwidth | 0:0.2.5-3.module+el8.10.0+1860+afcc1c71 | RLSA-2025:23530 |
| Rocky Linux:8 | python-wcwidth | 0:0.2.5-3.module+el8.10.0+1582+bc278001 | RLSA-2025:23530 |
| Rocky Linux:8 | python-wheel | 1:0.35.1-4.module+el8.10.0+1860+afcc1c71 | RLSA-2025:23530 |
| Rocky Linux:8 | python-wheel | 1:0.35.1-4.module+el8.10.0+1582+bc278001 | RLSA-2025:23530 |
| Rocky Linux:8 | python3x-pip | 0:20.2.4-9.module+el8.10.0+1860+afcc1c71 | RLSA-2025:23530 |
| Rocky Linux:8 | python3x-pip | 0:20.2.4-9.module+el8.10.0+1721+e52d6351 | RLSA-2025:23530 |
| Rocky Linux:8 | python3x-pyparsing | 0:2.4.7-5.module+el8.10.0+1582+bc278001 | RLSA-2025:23530 |
| Rocky Linux:8 | python3x-pyparsing | 0:2.4.7-5.module+el8.10.0+1860+afcc1c71 | RLSA-2025:23530 |
| Rocky Linux:8 | python3x-setuptools | 0:50.3.2-7.module+el8.10.0+2057+30213a2b | RLSA-2025:23530 |
| Rocky Linux:8 | python3x-six | 0:1.15.0-3.module+el8.10.0+1860+afcc1c71 | RLSA-2025:23530 |
| Rocky Linux:8 | python3x-six | 0:1.15.0-3.module+el8.10.0+1582+bc278001 | RLSA-2025:23530 |
| Rocky Linux:8 | scipy | 0:1.5.4-5.module+el8.10.0+1860+afcc1c71 | RLSA-2025:23530 |
| Rocky Linux:8 | scipy | 0:1.5.4-5.module+el8.10.0+1582+bc278001 | RLSA-2025:23530 |
| Ubuntu:22.04:LTS | python3.10 | 3.10.12-1~22.04.10 | USN-7570-1 |
| Ubuntu:22.04:LTS | python3.10 | 3.10.12-1~22.04.10 | UBUNTU-CVE-2025-4516 |
| Ubuntu:24.04:LTS | python3.12 | 3.12.3-1ubuntu0.6 | USN-7570-1 |
| Ubuntu:24.04:LTS | python3.12 | 3.12.3-1ubuntu0.6 | UBUNTU-CVE-2025-4516 |
| Ubuntu:25.10 | python3.14 | 3.14.0-1 | UBUNTU-CVE-2025-4516 |
| Ubuntu:26.04:LTS | python3.14 | 3.14.0-1 | UBUNTU-CVE-2025-4516 |
Affected products (as reported)
| Vendor | Product | Versions |
|---|---|---|
| Python Software Foundation | CPython | 0 – before 3.9.233.10.0 – before 3.10.183.11.0 – before 3.11.133.12.0 – before 3.12.113.13.0 – before 3.13.43.14.0a1 – before 3.14.0b2 |
Weakness: CWE-416 · Vector: 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
References
- https://github.com/python/cpython/issues/133767 issue-tracking
- https://github.com/python/cpython/pull/129648 patch
- https://mail.python.org/archives/list/security-announce@python.org/thread/L75IPBBTSCYEF56I2M4KIW353BB3AY74/ vendor-advisory
- https://github.com/python/cpython/commit/69b4387f78f413e8c47572a85b3478c47eba8142 patch
- https://github.com/python/cpython/commit/9f69a58623bd01349a18ba0c7a9cb1dad6a51e8e patch
- https://github.com/python/cpython/commit/4398b788ffc1f954a2c552da285477d42a571292 patch
- https://github.com/python/cpython/commit/6279eb8c076d89d3739a6edb393e43c7929b429d patch
- https://github.com/python/cpython/commit/73b3040f592436385007918887b7e2132aa8431f patch
- https://github.com/python/cpython/commit/8d35fd1b34935221aff23a1ab69a429dd156be77 patch
- https://github.com/python/cpython/commit/ab9893c40609935e0d40a6d2a7307ea51aec598b patch
- http://www.openwall.com/lists/oss-security/2025/05/16/4
- http://www.openwall.com/lists/oss-security/2025/05/19/1