CVE-2021-3177: 
Python vulnerability analysis and mitigation

Python 3.x through 3.9.1 has a buffer overflow vulnerability in PyCArgrepr in ctypes/callproc.c, which was discovered on January 16, 2021 and assigned CVE-2021-3177. This vulnerability affects Python versions 3.6.0 through 3.6.12, 3.7.0 through 3.7.9, 3.8.0 through 3.8.7 and 3.9.0 through 3.9.1 (Python Security).

The vulnerability occurs due to unsafe usage of sprintf in the PyCArgrepr function in ctypes/callproc.c. When processing floating-point numbers as untrusted input, particularly with values like 1e300, the resulting string representation exceeds the fixed 256-byte buffer size, causing a buffer overflow (Python Bug Tracker, CVE Details). The vulnerability has been assigned a CVSS score of 7.5, indicating high severity.

A successful exploitation of this vulnerability could lead to remote code execution in certain Python applications that accept floating-point numbers as untrusted input. The buffer overflow condition could allow attackers to execute arbitrary code with the privileges of the running Python process (NVD).

The vulnerability was fixed in Python versions 3.6.13, 3.7.10, 3.8.8, 3.9.2, and 3.10.0. The fix replaced the unsafe sprintf usage with Python unicode formatting in ctypes param representations. Users should upgrade to these or later versions. For Python 3.5 or lower, these versions are no longer receiving security fixes and will not be patched (Python Security).

The vulnerability caused significant disruption at major technology companies. According to reports, remediation of this vulnerability caused complete gridlock for internal tools at a certain FAANG company. The fix was rapidly deployed across various Linux distributions and enterprise systems, highlighting the widespread impact of the vulnerability (Hacker News).