🛡️ CVE-2021-3177 — libpython

🔴 CVSS 9.5 — Critical ✅ No Known Exploit OSV
9.5
CVSS Score
0 Low4 Medium7 High9 Critical10

Description

Python 3.x through 3.9.1 has a buffer overflow in PyCArg_repr in _ctypes/callproc.c, which may lead to remote code execution in certain Python applications that accept floating-point numbers as untrusted input, as demonstrated by a 1e300 argument to c_double.from_param. This occurs because sprintf is used unsafely.

Details

Severity CRITICAL
CVSS Score 9.5
CVSS Vector N/A
CWE N/A
Public Exploit ✅ No
Source OSV
Published 2025-08-11
Updated 2026-06-02
Modified 2025-08-11
Fix URL N/A

Affected Packages

Software From version Fixed in
libpython
python
python-min

References

Exploit Protection

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CVE-2021-3177 carries CVSS 9.5 Critical rating. BotEraser checks your installation against this and other known CVE records, and blocks IPs associated with exploit activity.

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