01 Record

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 Python applications that accept floating-point numbers as

CriticalPUBLISHEDCNA: mitre

CNA base score9.8 CVSS v3.xCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

View raw JSON

02 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

03 Exploitation and scoring

Exploitation

Public exploit code exists. CISA's assessment records a public proof of concept. That is not a report of exploitation in the wild.

SSVC decision

ExploitationpocPublic proof-of-concept exploit code exists. Not a report of exploitation in the wild.
AutomatableyesAn attacker can reliably automate reconnaissance through exploitation, so this scales.
Technical ImpacttotalSuccessful exploitation gives total control of the vulnerable component.

CISA publishes the decision points, not a final SSVC decision. The decision also depends on mission and well-being impact, which is a property of your deployment rather than of the vulnerability.

EPSS probability

24.21% probability of exploitation activity in the next 30 days.

EPSS percentile

Equal to or higher than the score of 97.8% of scored records. A rank, not a probability.

NVD base score

9.8 (CVSS v3.x), scored by the NVD independently of the CNA.

NVD CVSS vector

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

NVD analysis status

Modified. NVD last modified this record on 2026-10-14.

Red Hat severity

Moderate. Red Hat's rating for its own products, not a CVSS rating.

Exploit-prediction scores from FIRST. Independent scoring and analysis status from the NVD. Vendor severity from Red Hat. Exploitation assessment and catalog membership from CISA.

04 Metadata

Published

2021-01-19 00:00Z5 YR AGO

Last updated

2026-10-14 09:45Z15 DAYS AGO

Reserved

2021-01-19

Assigning CNA

mitre

Record state

PUBLISHED

Severity

Critical (CVSS 9.8)

CNA CVSS vector

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

Weaknesses

CWE-120Buffer Copy without Checking Size of Input ('Classic Buffer Overflow')Base

Data version

5.2

Document digest

297cdfa24e20b0cc6ade79b4e0b23f485269e77ba5782eb7f7a7396cc1173691

05 Affected products

VendorProductVersionsPlatforms

debiandebian_linuxNot specified—

fedoraprojectfedoraNot specified—

netappactive_iq_unified_managerNot specified—

netappontap_select_deploy_administration_utilityNot specified—

oraclecommunications_cloud_native_core_network_function_cloud_native_environmentNot specified—

oraclecommunications_offline_mediation_controllerNot specified—

oraclecommunications_pricing_design_centerNot specified—

oracleenterprise_manager_ops_centerNot specified—

oraclezfs_storage_appliance_kitNot specified—

pythonpythonNot specified—

redhatenterprise_linuxNot specified—

redhatrhel_software_collectionsNot specified—

06 References

bugs.python.orghttps://bugs.python.org/issue42938
github.comhttps://github.com/python/cpython/pull/24239
python-security.readthedocs.iohttps://python-security.readthedocs.io/vuln/ctypes-buffer-overflow-pycarg_repr.html
lists.fedoraproject.orgFEDORA-2021-faf88b9499https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/MGSV6BJQLRQ6RKVUXK7JGU7TP4QFGQXC/vendor-advisory
lists.fedoraproject.orgFEDORA-2021-cc3ff94cfchttps://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/NQPARTLNSFQVMMQHPNBFOCOZOO3TMQNA/vendor-advisory
security.gentoo.orgGLSA-202101-18https://security.gentoo.org/glsa/202101-18vendor-advisory
lists.fedoraproject.orgFEDORA-2021-e3a5a74610https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/Z7GZV74KM72O2PEJN2C4XP3V5Q5MZUOO/vendor-advisory
lists.fedoraproject.orgFEDORA-2021-ced31f3f0chttps://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/CCFZMVRQUKCBQIG5F2CBVADK63NFSE4A/vendor-advisory
lists.fedoraproject.orgFEDORA-2021-42ba9feb47https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/BRHOCQYX3QLDGDQGTWQAUUT2GGIZCZUO/vendor-advisory
lists.fedoraproject.orgFEDORA-2021-076a2dccbahttps://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/NXSMBHES3ANXXS2RSO5G6Q24BR4B2PWK/vendor-advisory
lists.fedoraproject.orgFEDORA-2021-851c6e4e2dhttps://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/V6XJAULOS5JVB2L67NCKKMJ5NTKZJBSD/vendor-advisory
lists.fedoraproject.orgFEDORA-2021-66547ff92dhttps://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/YDTZVGSXQ7HR7OCGSUHTRNTMBG43OMKU/vendor-advisory
lists.fedoraproject.orgFEDORA-2021-17668e344ahttps://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/Y4KSYYWMGAKOA2JVCQA422OINT6CKQ7O/vendor-advisory
lists.fedoraproject.orgFEDORA-2021-d5cde50865https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/FPE7SMXYUIWPOIZV4DQYXODRXMFX3C5E/vendor-advisory
lists.fedoraproject.orgFEDORA-2021-7547ad987fhttps://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/HCQTCSP6SCVIYNIRUJC5X7YBVUHPLSC4/vendor-advisory
lists.fedoraproject.orgFEDORA-2021-f4fd9372c7https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/NODWHDIFBQE5RU5PUWUVE47JOT5VCMJ2/vendor-advisory
lists.fedoraproject.orgFEDORA-2021-3352c1c802https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/MP572OLHMS7MZO4KUPSCIMSZIA5IZZ62/vendor-advisory
lists.apache.org[mina-dev] 20210225 [jira] [Created] (FTPSERVER-500) Security vulnerability in common/lib/log4j-1.2.17.jarhttps://lists.apache.org/thread.html/rf9fa47ab66495c78bb4120b0754dd9531ca2ff0430f6685ac9b07772%40%3Cdev.mina.apache.org%3Emailing-list
lists.fedoraproject.orgFEDORA-2021-907f3bacaehttps://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/FONHJIOZOFD7CD35KZL6SVBUTMBPGZGA/vendor-advisory
lists.debian.org[debian-lts-announce] 20210405 [SECURITY] [DLA 2619-1] python3.5 security updatehttps://lists.debian.org/debian-lts-announce/2021/04/msg00005.htmlmailing-list
www.oracle.comhttps://www.oracle.com//security-alerts/cpujul2021.html
news.ycombinator.comhttps://news.ycombinator.com/item?id=26185005
security.netapp.comhttps://security.netapp.com/advisory/ntap-20210226-0003/
www.oracle.comhttps://www.oracle.com/security-alerts/cpuoct2021.html
www.oracle.comhttps://www.oracle.com/security-alerts/cpujan2022.html
lists.debian.org[debian-lts-announce] 20220212 [SECURITY] [DLA 2919-1] python2.7 security updatehttps://lists.debian.org/debian-lts-announce/2022/02/msg00013.htmlmailing-list
www.oracle.comhttps://www.oracle.com/security-alerts/cpujul2022.html
lists.debian.org[debian-lts-announce] 20230524 [SECURITY] [DLA 3432-1] python2.7 security updatehttps://lists.debian.org/debian-lts-announce/2023/05/msg00024.htmlmailing-list
cert-portal.siemens.comhttps://cert-portal.siemens.com/productcert/html/ssa-398330.html

07 Fixed in

AlmaLinux 8

python-psycopg2-doc
Fixed in 2.7.5-7.module_el8.6.0+2781+fed64c13
python-sqlalchemy-doc
Fixed

A version is affected if any line below covers it.
- Affected before 1.3.2-2.module_el8.5.0+2569+5c5719bc
- Affected before 1.3.2-2.module_el8.6.0+2781+fed64c13
python2-Cython
Fixed in 0.28.1-7.module_el8.6.0+2781+fed64c13
python2-PyMySQL
Fixed in 0.8.0-10.module_el8.6.0+2781+fed64c13
python2-attrs
Fixed in 17.4.0-10.module_el8.6.0+2781+fed64c13
python2-backports
Fixed in 1.0-16.module_el8.6.0+2781+fed64c13
python2-backports-ssl_match_hostname
Fixed in 3.5.0.1-12.module_el8.6.0+2781+fed64c13
python2-chardet
Fixed in 3.0.4-10.module_el8.6.0+2781+fed64c13
python2-coverage
Fixed in 4.5.1-4.module_el8.6.0+2781+fed64c13
python2-dns
Fixed in 1.15.0-10.module_el8.6.0+2781+fed64c13
python2-docs
Fixed in 2.7.16-2.module_el8.6.0+2781+fed64c13
python2-docs-info
Fixed in 2.7.16-2.module_el8.6.0+2781+fed64c13
python2-docutils
Fixed in 0.14-12.module_el8.6.0+2781+fed64c13
python2-funcsigs
Fixed in 1.0.2-13.module_el8.6.0+2781+fed64c13
python2-idna
Fixed in 2.5-7.module_el8.6.0+2781+fed64c13
python2-ipaddress
Fixed in 1.0.18-6.module_el8.6.0+2781+fed64c13
python2-markupsafe
Fixed in 0.23-19.module_el8.6.0+2781+fed64c13
python2-mock
Fixed in 2.0.0-13.module_el8.6.0+2781+fed64c13
python2-numpy
Fixed in 1:1.14.2-16.module_el8.6.0+2781+fed64c13
python2-numpy-doc
Fixed in 1:1.14.2-16.module_el8.6.0+2781+fed64c13
python2-numpy-f2py
Fixed in 1:1.14.2-16.module_el8.6.0+2781+fed64c13
python2-pluggy
Fixed in 0.6.0-8.module_el8.6.0+2781+fed64c13
python2-psycopg2
Fixed in 2.7.5-7.module_el8.6.0+2781+fed64c13
python2-psycopg2-debug
Fixed in 2.7.5-7.module_el8.6.0+2781+fed64c13
python2-psycopg2-tests
Fixed in 2.7.5-7.module_el8.6.0+2781+fed64c13
python2-py
Fixed in 1.5.3-6.module_el8.6.0+2781+fed64c13
python2-pysocks
Fixed in 1.6.8-6.module_el8.6.0+2781+fed64c13
python2-pytest
Fixed in 3.4.2-13.module_el8.6.0+2781+fed64c13
python2-pytest-mock
Fixed in 1.9.0-4.module_el8.6.0+2781+fed64c13
python2-pytz
Fixed in 2017.2-12.module_el8.6.0+2781+fed64c13
python2-pyyaml
Fixed in 3.12-16.module_el8.6.0+2781+fed64c13
python2-requests
Fixed in 2.20.0-3.module_el8.6.0+2781+fed64c13
python2-rpm-macros
Fixed in 3-38.module_el8.6.0+2781+fed64c13
python2-setuptools
Fixed in 39.0.1-13.module_el8.6.0+2781+fed64c13
python2-setuptools-wheel
Fixed in 39.0.1-13.module_el8.6.0+2781+fed64c13
python2-setuptools_scm
Fixed in 1.15.7-6.module_el8.6.0+2781+fed64c13
python2-six
Fixed in 1.11.0-6.module_el8.6.0+2781+fed64c13
python2-sqlalchemy
Fixed in 1.3.2-2.module_el8.6.0+2781+fed64c13
python2-urllib3
Fixed in 1.24.2-3.module_el8.6.0+2781+fed64c13
python38-Cython
Fixed in 0.29.14-4.module_el8.6.0+2778+cd494b30

18 further packages in AlmaLinux 8 not shown (first 40 listed).

Arch Linux

python
Fixed in 3.9.2-1

Source: Arch Linux Security Tracker, the Arch Linux security team. Reformatted by exploit.cc.

CloudLinux 8

python-psycopg2-doc
Fixed in 2.7.5-7.module_el8.6.0+2781+fed64c13
python-sqlalchemy-doc
Fixed

A version is affected if any line below covers it.
- Affected before 1.3.2-2.module_el8.5.0+2569+5c5719bc
- Affected before 1.3.2-2.module_el8.6.0+2781+fed64c13
python2-Cython
Fixed in 0.28.1-7.module_el8.6.0+2781+fed64c13
python2-PyMySQL
Fixed in 0.8.0-10.module_el8.6.0+2781+fed64c13
python2-attrs
Fixed in 17.4.0-10.module_el8.6.0+2781+fed64c13
python2-backports
Fixed in 1.0-16.module_el8.6.0+2781+fed64c13
python2-backports-ssl_match_hostname
Fixed in 3.5.0.1-12.module_el8.6.0+2781+fed64c13
python2-chardet
Fixed in 3.0.4-10.module_el8.6.0+2781+fed64c13
python2-coverage
Fixed in 4.5.1-4.module_el8.6.0+2781+fed64c13
python2-dns
Fixed in 1.15.0-10.module_el8.6.0+2781+fed64c13
python2-docs
Fixed in 2.7.16-2.module_el8.6.0+2781+fed64c13
python2-docs-info
Fixed in 2.7.16-2.module_el8.6.0+2781+fed64c13
python2-docutils
Fixed in 0.14-12.module_el8.6.0+2781+fed64c13
python2-funcsigs
Fixed in 1.0.2-13.module_el8.6.0+2781+fed64c13
python2-idna
Fixed in 2.5-7.module_el8.6.0+2781+fed64c13
python2-ipaddress
Fixed in 1.0.18-6.module_el8.6.0+2781+fed64c13
python2-markupsafe
Fixed in 0.23-19.module_el8.6.0+2781+fed64c13
python2-mock
Fixed in 2.0.0-13.module_el8.6.0+2781+fed64c13
python2-numpy
Fixed in 1:1.14.2-16.module_el8.6.0+2781+fed64c13
python2-numpy-doc
Fixed in 1:1.14.2-16.module_el8.6.0+2781+fed64c13
python2-numpy-f2py
Fixed in 1:1.14.2-16.module_el8.6.0+2781+fed64c13
python2-pluggy
Fixed in 0.6.0-8.module_el8.6.0+2781+fed64c13
python2-psycopg2
Fixed in 2.7.5-7.module_el8.6.0+2781+fed64c13
python2-psycopg2-debug
Fixed in 2.7.5-7.module_el8.6.0+2781+fed64c13
python2-psycopg2-tests
Fixed in 2.7.5-7.module_el8.6.0+2781+fed64c13
python2-py
Fixed in 1.5.3-6.module_el8.6.0+2781+fed64c13
python2-pysocks
Fixed in 1.6.8-6.module_el8.6.0+2781+fed64c13
python2-pytest
Fixed in 3.4.2-13.module_el8.6.0+2781+fed64c13
python2-pytest-mock
Fixed in 1.9.0-4.module_el8.6.0+2781+fed64c13
python2-pytz
Fixed in 2017.2-12.module_el8.6.0+2781+fed64c13
python2-pyyaml
Fixed in 3.12-16.module_el8.6.0+2781+fed64c13
python2-requests
Fixed in 2.20.0-3.module_el8.6.0+2781+fed64c13
python2-rpm-macros
Fixed in 3-38.module_el8.6.0+2781+fed64c13
python2-setuptools
Fixed in 39.0.1-13.module_el8.6.0+2781+fed64c13
python2-setuptools-wheel
Fixed in 39.0.1-13.module_el8.6.0+2781+fed64c13
python2-setuptools_scm
Fixed in 1.15.7-6.module_el8.6.0+2781+fed64c13
python2-six
Fixed in 1.11.0-6.module_el8.6.0+2781+fed64c13
python2-sqlalchemy
Fixed in 1.3.2-2.module_el8.6.0+2781+fed64c13
python2-urllib3
Fixed in 1.24.2-3.module_el8.6.0+2781+fed64c13
python38-Cython
Fixed in 0.29.14-4.module_el8.6.0+2778+cd494b30

18 further packages in CloudLinux 8 not shown (first 40 listed).

Derived from AlmaLinux 8. Partial coverage: only packages taken from AlmaLinux 8 are listed.

Debian 11

python2.7
Fixed in 2.7.18-2
python3.9
Fixed in 3.9.1-3

Source: Debian Security Tracker, the Debian security team. Received through OSV.dev. Reformatted by exploit.cc.

Ubuntu 16.04 LTS

python2.7
Fixed in 2.7.12-1ubuntu0~16.04.18
python3.5
Fixed in 3.5.2-2ubuntu0~16.04.13

Source: Ubuntu, Canonical Ltd. Licensed under CC BY-SA 4.0. Received through OSV.dev. Reformatted by exploit.cc.

Ubuntu 18.04 LTS

python2.7
Fixed in 2.7.17-1~18.04ubuntu1.6
python3.6
Fixed in 3.6.9-1~18.04ubuntu1.4
python3.7
Fixed in 3.7.5-2~18.04.4
python3.8
Fixed in 3.8.0-3~18.04.1

Source: Ubuntu, Canonical Ltd. Licensed under CC BY-SA 4.0. Received through OSV.dev. Reformatted by exploit.cc.

Ubuntu 20.04 LTS

python2.7
Fixed in 2.7.18-1~20.04.1
python3.8
Fixed in 3.8.5-1~20.04.2
python3.9
Fixed in 3.9.5-3~20.04.1

Source: Ubuntu, Canonical Ltd. Licensed under CC BY-SA 4.0. Received through OSV.dev. Reformatted by exploit.cc.

Ubuntu Pro 14.04 LTS

python2.7
Fixed in 2.7.6-8ubuntu0.6+esm10
Available with Ubuntu Pro (Infra-only): https://ubuntu.com/pro
python3.4
Fixed in 3.4.3-1ubuntu1~14.04.7+esm10
Available with Ubuntu Pro (Infra-only): https://ubuntu.com/pro
python3.5
Fixed in 3.5.2-2ubuntu0~16.04.4~14.04.1+esm1
Available with Ubuntu Pro (Infra-only): https://ubuntu.com/pro

Source: Ubuntu, Canonical Ltd. Licensed under CC BY-SA 4.0. Received through OSV.dev. Reformatted by exploit.cc.

A release or ecosystem missing from this list has no record here. It may be unaffected or not covered by the source. Source notices and licences.