The email module of Python through 3.11.3 incorrectly parses e-mail addresses that contain a special character.

published 2023-04-18 3 y ago modified 2026-10-16 24 d ago also BIT-libpython-2023-27043 , BIT-python-2023-27043 , BIT-python-min-2023-27043 , EUVD-2023-30832

cvss: 5.3; version 3.1, CNA
cisa kev: Not listed; not in CISA's catalog
epss: 2.5%; EPSS 2.5% chance of exploitation in 30 days, percentile 85%
public exploits: 0; none known

The email module of Python through 3.11.3 incorrectly parses e-mail addresses that contain a special character. The wrong portion of an RFC2822 header is identified as the value of the addr-spec. In some applications, an attacker can bypass a protection mechanism in which application access is granted only after verifying receipt of e-mail to a specific domain (e.g., only @company.example.com addresses may be used for signup). This occurs in email/_parseaddr.py in recent versions of Python.

Vendor advisories

What the vendors themselves say about their products: affected, fixed or not affected, and what to do.

red hat product security vex CVE-2023-27043 updated 2026-11-09 cvss 5.3

python: Parsing errors in email/_parseaddr.py lead to incorrect value in email address part of tuple

Red Hat Enterprise Linux 6 python, tkinter, python-libs, python-test, python-tools Red Hat Enterprise Linux 7 python, python3, tkinter, python-libs, python-test, python-tools, +4 more
affected: no fix planned “Out of support scope”
Red Hat Enterprise Linux 8 python2, python2-libs, python2-test, python2-tools, python2-tkinter Red Hat Software Collections rh-python38-python, rh-python38-python-idle, rh-python38-python-libs, rh-python38-python-test, rh-python38-python-tkinter, rh-python38-python-rpm-macros, +1 more
affected: no fix planned “Will not fix”
Red Hat CodeReady Linux Builder (v. 9) python3 3.9.18-1.el9_3.1, python3-idle 3.9.18-1.el9_3.1, python3-test 3.9.18-1.el9_3.1, python3-tkinter 3.9.18-1.el9_3.1
fixed: vendor fix RHSA-2024:0466
Red Hat CodeReady Linux Builder EUS (v.9.2) python3 3.9.16-1.el9_2.3, python3-idle 3.9.16-1.el9_2.3, python3-test 3.9.16-1.el9_2.3, python3-tkinter 3.9.16-1.el9_2.3
fixed: vendor fix RHSA-2024:0454
Red Hat Enterprise Linux AppStream (v. 8) python3.11 3.11.7-1.el8, python3.11-libs 3.11.7-1.el8, python3-idle 3.6.8-56.el8_9.3, python3-test 3.6.8-56.el8_9.3, python3.11-tkinter 3.11.7-1.el8, platform-python 3.6.8-56.el8_9.3, +57 more
fixed: vendor fix RHSA-2024:2985
Red Hat Enterprise Linux AppStream (v. 9) python3.11 3.11.7-1.el9, python3.11-libs 3.11.7-1.el9, python3.11-tkinter 3.11.7-1.el9, python3-tkinter 3.9.18-1.el9_3.1, python-unversioned-command 3.9.18-1.el9_3.1
fixed: vendor fix RHSA-2024:0466
Red Hat Enterprise Linux AppStream EUS (v.8.6) python3-idle 3.6.8-47.el8_6.4, python3-test 3.6.8-47.el8_6.4, platform-python 3.6.8-47.el8_6.4, python3-tkinter 3.6.8-47.el8_6.4
fixed: vendor fix RHSA-2024:0430
Red Hat Enterprise Linux AppStream EUS (v.8.8) python3-idle 3.6.8-51.el8_8.4, python3-test 3.6.8-51.el8_8.4, platform-python 3.6.8-51.el8_8.4, python3-tkinter 3.6.8-51.el8_8.4
fixed: vendor fix RHSA-2024:0586

show 10 more

Red Hat Enterprise Linux AppStream EUS (v.9.2) python3-tkinter 3.9.16-1.el9_2.3, python-unversioned-command 3.9.16-1.el9_2.3
fixed: vendor fix RHSA-2024:0454
Red Hat Enterprise Linux BaseOS (v. 8) python3 3.6.8-56.el8_9.3, python3-libs 3.6.8-56.el8_9.3, python3-test 3.6.8-56.el8_9.3, platform-python 3.6.8-56.el8_9.3
fixed: vendor fix RHSA-2024:0256
Red Hat Enterprise Linux BaseOS (v. 9) python3 3.9.18-1.el9_3.1, python3.9 3.9.18-1.el9_3.1, python3-libs 3.9.18-1.el9_3.1
fixed: vendor fix RHSA-2024:0466
Red Hat Enterprise Linux BaseOS EUS (v.8.6) python3 3.6.8-47.el8_6.4, python3-libs 3.6.8-47.el8_6.4, python3-test 3.6.8-47.el8_6.4, platform-python 3.6.8-47.el8_6.4
fixed: vendor fix RHSA-2024:0430
Red Hat Enterprise Linux BaseOS EUS (v.8.8) python3 3.6.8-51.el8_8.4, python3-libs 3.6.8-51.el8_8.4, python3-test 3.6.8-51.el8_8.4, platform-python 3.6.8-51.el8_8.4
fixed: vendor fix RHSA-2024:0586
Red Hat Enterprise Linux BaseOS EUS (v.9.2) python3 3.9.16-1.el9_2.3, python3.9 3.9.16-1.el9_2.3, python3-libs 3.9.16-1.el9_2.3
fixed: vendor fix RHSA-2024:0454
Red Hat Enterprise Linux CRB (v. 8) python3.11 3.11.7-1.el8, python3.11-idle 3.11.7-1.el8, python3.11-test 3.11.7-1.el8, python3.11-tkinter 3.11.7-1.el8, pytest 6.0.2-2.module+el8.9.0+19644+d68f775d, Cython 0.29.21-5.module+el8.9.0+19644+d68f775d, +20 more
fixed: vendor fix RHSA-2024:2985
Red Hat Enterprise Linux CRB (v. 9) python3.11 3.11.7-1.el9, python3.11-idle 3.11.7-1.el9, python3.11-test 3.11.7-1.el9, python3.11-tkinter 3.11.7-1.el9
fixed: vendor fix RHSA-2024:2292
Red Hat RHODF 4.15 for RHEL 9 odf4/cephcsi-rhel9 v4.15.0-37, odf4/odf-cli-rhel9 v4.15.0-22, odf4/mcg-core-rhel9 v4.15.0-68, odf4/odf-console-rhel9 v4.15.0-57, odf4/mcg-rhel9-operator v4.15.0-39, odf4/ocs-rhel9-operator v4.15.0-79, +20 more
fixed: vendor fix RHSA-2024:1383
Red Hat Enterprise Linux 8 pytz, babel, numpy, scipy, Cython, PyYAML, +82 more
not affected: vulnerable code not present

Red Hat CSAF VEX © Red Hat, Inc., from https://security.access.redhat.com/data/csaf/v2/vex/; changed: reduced to product statuses and remediations. CC BY 4.0 · csaf

cisa ICSA-26-134-16 updated 2026-05-14 cvss 5.3

Siemens Ruggedcom Rox

Siemens RUGGEDCOM ROX MX5000 < 2.17.1 Siemens RUGGEDCOM ROX MX5000RE < 2.17.1 Siemens RUGGEDCOM ROX RX1400 < 2.17.1 Siemens RUGGEDCOM ROX RX1500 < 2.17.1 Siemens RUGGEDCOM ROX RX1501 < 2.17.1 Siemens RUGGEDCOM ROX RX1510 < 2.17.1

+5 more productsfewer

Siemens RUGGEDCOM ROX RX1511 < 2.17.1 Siemens RUGGEDCOM ROX RX1512 < 2.17.1 Siemens RUGGEDCOM ROX RX1524 < 2.17.1 Siemens RUGGEDCOM ROX RX1536 < 2.17.1 Siemens RUGGEDCOM ROX RX5000 < 2.17.1

affected: fixed in V2.17.1 support.industry.siemens.com

Facts from CISA's republication of the vendor's own advisory (CSAF); the linked advisory is the authoritative source. CISA notification · csaf

CISA SSVC

Exploitation: Proof of concept is public
Automatable: yes
Technical impact: partial
Assessed: 10 mo ago (2025-12-17)

Exploit prediction

2.53% chance of exploitation in the next 30 days, higher than 85% of all scored CVEs (FIRST EPSS, 2026-11-08).

Exploits and checks

github.com https://github.com/python/cpython/issues/102988 referenced PoC, tagged "exploit" by a source, unverified

CVSS scores

assigned by	version	score	vector
CISA ADP	3.1	5.3	CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:N
NVD	3.1	5.3	CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:N
CNA	3.1	5.3	CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:N
OSV	3.1	5.3	CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:N

Affected packages

ecosystem	package	affected	fixed in
bitnami	libpython	<3.8.20 >=3.10.0, <3.10.15 >=3.11.0, <3.11.10 >=3.12.0, <3.12.6 >=3.9.0, <3.9.20	3.8.20 3.10.15 3.11.10 3.12.6 3.9.20
bitnami	python	<3.8.20 >=3.10.0, <3.10.15 >=3.11.0, <3.11.10 >=3.12.0, <3.12.6 >=3.9.0, <3.9.20	3.8.20 3.10.15 3.11.10 3.12.6 3.9.20
bitnami	python-min	<3.8.20 >=3.10.0, <3.10.15 >=3.11.0, <3.11.10 >=3.12.0, <3.12.6 >=3.9.0, <3.9.20	3.8.20 3.10.15 3.11.10 3.12.6 3.9.20

Affected products

Siemens RUGGEDCOM ROX MX5000
Siemens RUGGEDCOM ROX MX5000RE
Siemens RUGGEDCOM ROX RX1400
Siemens RUGGEDCOM ROX RX1500
Siemens RUGGEDCOM ROX RX1501
Siemens RUGGEDCOM ROX RX1510
Siemens RUGGEDCOM ROX RX1511
Siemens RUGGEDCOM ROX RX1512
Siemens RUGGEDCOM ROX RX1524
Siemens RUGGEDCOM ROX RX1536
Siemens RUGGEDCOM ROX RX5000

Classification

Weakness

CWE-20 Improper Input Validation
CWE-1286 Improper Validation of Syntactic Correctness of Input

References

github.com /python/cpython/issues/102988
exploit, issue-tracking, evidence
lists.fedoraproject.org /archives/list/package-announce%40lists.fedoraproject.org/message/ORLXS5YTKN65E2Q2NWKXMFS5FWQHRNZW/
vendor-advisory, third-party-advisory, advisory
lists.fedoraproject.org /archives/list/package-announce%40lists.fedoraproject.org/message/PHVGRKQAGANCSGFI3QMYOCIMS4IFOZA5/
vendor-advisory, third-party-advisory, advisory
lists.fedoraproject.org /archives/list/package-announce%40lists.fedoraproject.org/message/PU6Y2S5CBN5BWCBDAJFTGIBZLK3S2G3J/
vendor-advisory, third-party-advisory, advisory
lists.fedoraproject.org /archives/list/package-announce%40lists.fedoraproject.org/message/XWMBD4LNHWEXRI6YVFWJMTJQUL5WOFTS/
vendor-advisory, third-party-advisory, advisory
lists.fedoraproject.org /archives/list/package-announce%40lists.fedoraproject.org/message/4ZAEFSFZDNBNJPNOUTLG5COISGQDLMGV/
vendor-advisory, third-party-advisory, advisory
lists.fedoraproject.org /archives/list/package-announce%40lists.fedoraproject.org/message/SINP4OVYNB2AGDYI2GS37EMW3H3F7XPZ/
vendor-advisory, third-party-advisory, advisory
lists.fedoraproject.org /archives/list/package-announce%40lists.fedoraproject.org/message/VZXC32CJ7TWDPJO6GY2XIQRO7JZX5FLP/
vendor-advisory, third-party-advisory, advisory
lists.fedoraproject.org /archives/list/package-announce%40lists.fedoraproject.org/message/RDDC2VOX7OQC6OHMYTVD4HLFZIV6PYBC/
vendor-advisory, third-party-advisory, advisory
lists.fedoraproject.org /archives/list/package-announce%40lists.fedoraproject.org/message/NEUNZSZ3CVSM2QWVYH3N2XGOCDWNYUA3/
vendor-advisory, third-party-advisory, advisory
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vendor-advisory, third-party-advisory, advisory
lists.fedoraproject.org /archives/list/package-announce%40lists.fedoraproject.org/message/75DTHSTNOFFNAWHXKMDXS7EJWC6W2FUC/
vendor-advisory, third-party-advisory, advisory
lists.fedoraproject.org /archives/list/package-announce%40lists.fedoraproject.org/message/P2W2BZQIHMCKRI5FNBJERFYMS5PK6TAH/
vendor-advisory, third-party-advisory, advisory
lists.fedoraproject.org /archives/list/package-announce%40lists.fedoraproject.org/message/ARI7VDSNTQVXRQFM6IK5GSSLEIYV4VZH/
vendor-advisory, third-party-advisory, advisory
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lists.fedoraproject.org /archives/list/package-announce%40lists.fedoraproject.org/message/P2MAICLFDDO3QVNHTZ2OCERZQ34R2PIC/
vendor-advisory, third-party-advisory, advisory
lists.fedoraproject.org /archives/list/package-announce%40lists.fedoraproject.org/message/HXYVPEZUA3465AEFX5JVFVP7KIFZMF3N/
vendor-advisory, third-party-advisory, advisory
lists.fedoraproject.org /archives/list/package-announce%40lists.fedoraproject.org/message/QDRDDPDN3VFIYXJIYEABY6USX5EU66AG/
vendor-advisory, third-party-advisory, advisory
lists.fedoraproject.org /archives/list/package-announce%40lists.fedoraproject.org/message/BQAKLUJMHFGVBRDPEY57BJGNCE5UUPHW/
vendor-advisory, third-party-advisory, advisory
python.org
vendor-advisory, advisory
python-security.readthedocs.io /vuln/email-parseaddr-realname.html
vendor-advisory, advisory
security.netapp.com /advisory/ntap-20230601-0003/
third-party-advisory, advisory
lists.fedoraproject.org /archives/list/package-announce@lists.fedoraproject.org/message/4ZAEFSFZDNBNJPNOUTLG5COISGQDLMGV/
third-party-advisory, advisory
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third-party-advisory, advisory
lists.fedoraproject.org /archives/list/package-announce@lists.fedoraproject.org/message/PHVGRKQAGANCSGFI3QMYOCIMS4IFOZA5/
third-party-advisory, advisory
lists.fedoraproject.org /archives/list/package-announce@lists.fedoraproject.org/message/PU6Y2S5CBN5BWCBDAJFTGIBZLK3S2G3J/
third-party-advisory, advisory
lists.fedoraproject.org /archives/list/package-announce@lists.fedoraproject.org/message/QDRDDPDN3VFIYXJIYEABY6USX5EU66AG/
third-party-advisory, advisory
lists.fedoraproject.org /archives/list/package-announce@lists.fedoraproject.org/message/RDDC2VOX7OQC6OHMYTVD4HLFZIV6PYBC/
third-party-advisory, advisory
lists.fedoraproject.org /archives/list/package-announce@lists.fedoraproject.org/message/SINP4OVYNB2AGDYI2GS37EMW3H3F7XPZ/
advisory
lists.fedoraproject.org /archives/list/package-announce@lists.fedoraproject.org/message/VZXC32CJ7TWDPJO6GY2XIQRO7JZX5FLP/
advisory
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advisory
lists.fedoraproject.org /archives/list/package-announce@lists.fedoraproject.org/message/YQVY5C5REXWJIORJIL2FIL3ALOEJEF72/
advisory
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third-party-advisory, advisory
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third-party-advisory, advisory
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third-party-advisory, advisory
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third-party-advisory, advisory
lists.fedoraproject.org /archives/list/package-announce@lists.fedoraproject.org/message/NEUNZSZ3CVSM2QWVYH3N2XGOCDWNYUA3/
third-party-advisory, advisory
lists.fedoraproject.org /archives/list/package-announce@lists.fedoraproject.org/message/ORLXS5YTKN65E2Q2NWKXMFS5FWQHRNZW/
third-party-advisory, advisory
lists.fedoraproject.org /archives/list/package-announce@lists.fedoraproject.org/message/P2MAICLFDDO3QVNHTZ2OCERZQ34R2PIC/
third-party-advisory, advisory
seclists.org /fulldisclosure/2025/Apr/8
lists.debian.org /debian-lts-announce/2024/11/msg00024.html
lists.debian.org /debian-lts-announce/2024/12/msg00000.html
lists.fedoraproject.org /archives/list/package-announce@lists.fedoraproject.org/message/P2W2BZQIHMCKRI5FNBJERFYMS5PK6TAH/
third-party-advisory, advisory
nvd.nist.gov /vuln/detail/CVE-2023-27043
web

Sources

Fencer Vulns keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.

CPEs and fixed versions use Anchore's correction of NVD's data: Adjust affected version ranges to account for backports.

Summary

Patch / fix