CVE-2021-3177
criticalPython 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 tha…
Vendor / product: Python — python
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.
CVSS
9.8
9.8 (CVSS v3.1)
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H Severity source: NVD CVSS v3.1 (nvd@nist.gov)
Timeline (UTC)
Published: 2021-01-19 06:15
Modified: 2026-10-14 10:17
NVD status: Modified
Last synced 2 days ago
Verified against the source API 2026-10-27 07:06 UTC
Exploitation
Not listed in CISA KEV (as of last catalog sync)
Absence from KEV does not mean a CVE is not exploited. Exploitation status: unknown (no authoritative evidence in our sources).
Affected products
python / python ≥3.6.0 ≤3.6.12, ≥3.7.0 ≤3.7.9, ≥3.8.0 ≤3.8.7, ≥3.9.0 ≤3.9.1
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
Weakness classification (CWE)
Source: NVD / CISA. “NVD-CWE-Other” and “NVD-CWE-noinfo” mean NVD could not assign a specific weakness.
Mitigation & advisories
Vendor advisory: https://bugs.python.org/issue42938
Vendor advisory: https://bugs.python.org/issue42938
Patch / mitigation: https://bugs.python.org/issue42938
Patch / mitigation: https://github.com/python/cpython/pull/24239
Patch / mitigation: https://python-security.readthedocs.io/vuln/ctypes-buffer-overflow-pycarg_repr.html
Patch / mitigation: https://www.oracle.com//security-alerts/cpujul2021.html
Patch / mitigation: https://www.oracle.com/security-alerts/cpujan2022.html
Patch / mitigation: https://www.oracle.com/security-alerts/cpujul2022.html
Patch / mitigation: https://www.oracle.com/security-alerts/cpuoct2021.html
Patch / mitigation: https://bugs.python.org/issue42938
Patch / mitigation: https://github.com/python/cpython/pull/24239
References
- https://bugs.python.org/issue42938 cve@mitre.org
- https://github.com/python/cpython/pull/24239 cve@mitre.org
- https://lists.apache.org/thread.html/rf9fa47ab66495c78bb4120b0754dd9531ca2ff0430f6685ac9b0... cve@mitre.org
- https://lists.debian.org/debian-lts-announce/2021/04/msg00005.html cve@mitre.org
- https://lists.debian.org/debian-lts-announce/2022/02/msg00013.html cve@mitre.org
- https://lists.debian.org/debian-lts-announce/2023/05/msg00024.html cve@mitre.org
- https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/m... cve@mitre.org
- https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/m... cve@mitre.org
- https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/m... cve@mitre.org
- https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/m... cve@mitre.org
- https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/m... cve@mitre.org
- https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/m... cve@mitre.org
- https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/m... cve@mitre.org
- https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/m... cve@mitre.org
- https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/m... cve@mitre.org
- https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/m... cve@mitre.org
- https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/m... cve@mitre.org
- https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/m... cve@mitre.org
- https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/m... cve@mitre.org
- https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/m... cve@mitre.org
- https://news.ycombinator.com/item?id=26185005 cve@mitre.org
- https://python-security.readthedocs.io/vuln/ctypes-buffer-overflow-pycarg_repr.html cve@mitre.org
- https://security.gentoo.org/glsa/202101-18 cve@mitre.org
- https://security.netapp.com/advisory/ntap-20210226-0003/ cve@mitre.org
- https://www.oracle.com//security-alerts/cpujul2021.html cve@mitre.org
Data sources
NVD CVE API 2.0 — fetched 2026-10-27 07:06 UTC · record ↗