CVE-2023-6507 Groups not dropped before running subprocess when using empty 'extra_groups' parameter

2023-12-0818:20:49

CWE-269

PSF

github.com

cpython 3.12.0

subprocess module

posix platforms

cpython 3.12.1

extra_groups parameter

setgroups system call

privilege.

CVSS3

6.1

Attack Vector

ADJACENT

Attack Complexity

LOW

Privileges Required

HIGH

User Interaction

NONE

Scope

UNCHANGED

Confidentiality Impact

HIGH

Integrity Impact

HIGH

Availability Impact

NONE

CVSS:3.1/AV:A/AC:L/PR:H/UI:N/S:U/C:H/I:H/A:N

AI Score

6.8

Confidence

Low

SSVC

Exploitation

none

Automatable

Technical Impact

total

JSON

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).

ADP Affected

[
  {
    "cpes": [
      "cpe:2.3:a:python:cpython:3.13.0:*:*:*:*:*:*:*"
    ],
    "vendor": "python",
    "product": "cpython",
    "versions": [
      {
        "status": "affected",
        "version": "3.13.0"
      }
    ],
    "defaultStatus": "unknown"
  },
  {
    "cpes": [
      "cpe:2.3:a:python:cpython:*:*:*:*:*:*:*:*"
    ],
    "vendor": "python",
    "product": "cpython",
    "versions": [
      {
        "status": "affected",
        "version": "3.12.0"
      }
    ],
    "defaultStatus": "unknown"
  }
]