Description
An issue was found in CPython 3.12.0 `subprocess` module on POSIX platforms. The issue was fixed in CPython 3.12.1 and does not affect other stable releases. When using the `extra_groups=` parameter with an empty list as a value (ie `extra_groups=[]`) the logic regressed to not call `setgroups(0, NULL)` before calling `exec()`, thus not dropping the original processes' groups before starting the new process. There is no issue when the parameter isn't used or when any value is used besides an empty list. This issue only impacts CPython processes run with sufficient privilege to make the `setgroups` system call (typically `root`).
Affected products
python: python
References10
- github.com/python/cpython/issues/112334 Issue TrackingPatch
- github.com/python/cpython/issues/112334 Issue TrackingPatch
- github.com/python/cpython/commit/10e9bb13b8dcaa414645b9bd10718d…
- github.com/python/cpython/commit/85bbfa8a4bbdbb61a3a84fbd7cb29a…
- github.com/python/cpython/commit/9fe7655c6ce0b8e9adc229daf681b6…
- mail.python.org/archives/list/[email protected]/thre… Third Party Advisory
- github.com/python/cpython/commit/10e9bb13b8dcaa414645b9bd10718d…
- github.com/python/cpython/commit/85bbfa8a4bbdbb61a3a84fbd7cb29a…
- github.com/python/cpython/commit/9fe7655c6ce0b8e9adc229daf681b6…
- mail.python.org/archives/list/[email protected]/thre… Third Party Advisory
Metrics
- CVSS 3.1
-
4.9
MEDIUM
Score source: NVD
CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:U/C:N/I:H/A:N - EPSS — exploit probability
- 1% percentile: 71 · as of 5 November 2026
- CWE
- CWE-269
Could this be exploited in your environment?
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