CVE-2021-3177: 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 Pyth

Affected versions

NVD version ranges (for catalog products). Add the product to your stack with a version and matching uses these.

• debian debian linux9.0
• fedoraproject fedora32
• fedoraproject fedora33
• netapp active iq unified managerall versions
• netapp ontap select deploy administration utilityall versions
• oracle communications cloud native core network function cloud native environment22.2.0
• oracle communications offline mediation controller12.0.0.3.0
• oracle communications pricing design center12.0.0.3.0
• oracle enterprise manager ops center12.4.0.0
• oracle zfs storage appliance kit8.8
• python python3.9.0 and later · up to 3.9.1 inclusive
• python python3.8.0 and later · up to 3.8.7 inclusive
• python python3.7.0 and later · up to 3.7.9 inclusive
• python python3.6.0 and later · up to 3.6.12 inclusive

Package-level exposure

OSV and GitHub Advisory data: ecosystem, package and range. SBOM matching uses this table.

Other highest-scoring records for the same primary product.

• CVE-2016-5636Integer overflow in the get_data function in zipimport.c in CPython (aka Python) before 2.7.12, 3.x before 3.4.5, and 3.5.x before 3.5.2 all
  47Plan
• CVE-2007-4559Directory traversal vulnerability in the (1) extract and (2) extractall functions in the tarfile module in Python allows user-assisted remot
  47Plan
• CVE-2014-4650The CGIHTTPServer module in Python 2.7.5 and 3.3.4 does not properly handle URLs in which URL encoding is used for path separators, which al
  46Plan

Published before and after this one in the same product

• ← EarlierCVE-2020-26116Sep 27, 2020 · http.client in Python 3.x before 3.5.10, 3.6.x before 3.6.12, 3.7.x before 3.7.9, and 3.8.x before 3.8.5 allows CRLF injection if the attack
  30Monitor
• ← EarlierCVE-2020-27619Oct 22, 2020 · In Python 3 through 3.9.0, the Lib/test/multibytecodec_support.py CJK codec tests call eval() on content retrieved via HTTP.
  42Plan
• Later →CVE-2021-23336Feb 15, 2021 · The package python/cpython from 0 and before 3.6.13, from 3.7.0 and before 3.7.10, from 3.8.0 and before 3.8.8, from 3.9.0 and before 3.9.2
  35Monitor

FIRST EPSS daily score; only changes of 0.01 or more are recorded (step chart).

Root cause

When data is copied, the source length is not compared with the size of the destination buffer. Excess data overwrites adjacent memory.

A representative example of this vulnerability class. Not the vendor's source code; it shows the faulty pattern and its fix.

1char buf[256];2memcpy(buf, pkt->data, pkt->len);

1char buf[256];2if (pkt->len > sizeof(buf)) {3  return -EINVAL;4}5memcpy(buf, pkt->data, pkt->len);

Attack context

MITRE CAPEC attack patterns and ATT&CK techniques for this weakness class (CWE). A starting point for detection rules and threat hunting.