Cyber Resilience

CVE-2021-3177

CriticalPublic PoC

Published: 19 January 2021

Published
19 January 2021
Modified
18 December 2025
KEV Added
Patch
CVSS Score v3.1 9.8 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
EPSS Score 0.0007 22.0th percentile
Risk Priority 20 60% EPSS · 20% KEV · 20% CVSS

Summary

CVE-2021-3177 is a critical-severity Classic Buffer Overflow (CWE-120) vulnerability in Python Python. Its CVSS base score is 9.8 (Critical).

Operationally, ranked at the 22.0th percentile by exploit likelihood (below the median); it is not currently listed in the CISA KEV catalog; a public proof-of-concept is referenced.

EU & UK References

Vulnerability details

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…

more

because sprintf is used unsafely.

CWE(s)

Related Threats

No named actor attribution yet. ATT&CK technique mapping in progress for this CVE.

Affected Assets

python
python
3.6.0 — 3.6.12 · 3.7.0 — 3.7.9 · 3.8.0 — 3.8.7
fedoraproject
fedora
32, 33
netapp
active iq unified manager
all versions
netapp
ontap select deploy administration utility
all versions
debian
debian linux
9.0
oracle
communications cloud native core network function cloud native environment
22.2.0
oracle
communications offline mediation controller
12.0.0.3.0
oracle
communications pricing design center
12.0.0.3.0
oracle
enterprise manager ops center
12.4.0.0
oracle
zfs storage appliance kit
8.8

Mitigating Controls

Likely Mitigating Controls AI

Per-CVE control mapping for this CVE has not run yet; the list below is derived from the weakness types (CWEs) cited in the NVD entry.

addresses: CWE-120

Platform-independent managed code eliminates the need for unchecked native buffer copies that are the root cause of classic buffer overflows.

References