Public proof of conceptFix available

CVE-2023-27043

Q: Is CVE-2023-27043 actively exploited?

A proof-of-concept exploit exists for CVE-2023-27043, but active exploitation has not been confirmed at this time.

Q: What is the CVSS score for CVE-2023-27043?

CVE-2023-27043 has a CVSS v3 base score of 5.3 (MEDIUM severity), with vector string CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:N.

A public proof of concept exists; no exploitation attested.

Published2023-04-19
Fixed in3.12.6 · 3.11.10 · 3.10.15 · 3.9.20 · 3.8.20
WeaknessCWE-1286 · CWE-20

Am I affected?

With a domain, we read the version its public headers and pages expose. A distribution build can carry the fix under an older number.

Description

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.

Timeline

dates in UTC

2023-04-1900:15CVE publishedNVD

Observed activity

isMalicious corpus · updated 2026-10-28 15:37 UTC

Indicators tagged with this CVE, per day0 indicators over 7 days

Block these indicators

Firewall list (EDL, text): https://api.ismalicious.com/edl/cve/CVE-2023-27043?format=txt
CSV export: https://api.ismalicious.com/edl/cve/CVE-2023-27043?format=csv
TAXII collection of exploited CVEs
The EDL and CSV take an API key on the Pro plan.

Versions per branch

NVD · OSV

Python

Branch	Affected	Fixed in	Source
3.12	≥ 3.12.0, < 3.12.6	3.12.6	NVD · OSV
3.11	≥ 3.11.0, < 3.11.10	3.11.10	NVD · OSV
3.10	≥ 3.10.0, < 3.10.15	3.10.15	NVD · OSV
3.9	≥ 3.9.0, < 3.9.20	3.9.20	NVD · OSV
3.x	≥ 3.0, < 3.8.20	3.8.20	NVD
3.8	< 3.8.20	3.8.20	OSV
2.7	≤ 2.7.18	no fix published	NVD

Fedoraproject fedora

Branch	Affected	Fixed in	Source
38.x	= 38	no fix published	NVD
39.x	= 39	no fix published	NVD

Netapp active iq unified manager

Branch	Affected	Fixed in	Source
—	all versions	no fix published	NVD

1 more product in the sources.

as publishedRanges as NVD and OSV publish them; a distribution’s build can be fixed under an older number.

Distribution builds and vendor advisories

Packages from OSV.dev and products from the vendors' CSAF advisories.

version not verifiedVersions not verified: read as OSV.dev and the vendors publish them, not checked against each vendor's release list.

Packages

platform-pythonAlmaLinux:8all versions · fixed in 3.6.8-56.el8_9.3.alma.1and 6 other packages
python3AlmaLinux:9all versions · fixed in 3.9.18-1.el9_3.1and 7 other packages
python3.11AlmaLinux:9all versions · fixed in 3.11.7-1.el9and 6 other packages
python3.11AlmaLinux:8all versions · fixed in 3.11.7-1.el8and 7 other packages
python39AlmaLinux:8all versions · fixed in 3.9.18-3.module_el8.10.0+3765+2f9a457dand 7 other packages
python39-attrsAlmaLinux:8all versions · fixed in 20.3.0-2.module_el8.6.0+2780+a40f65e1
python39-cffiAlmaLinux:8all versions · fixed in 1.14.3-2.module_el8.6.0+3248+c431e88c
python39-cffiAlmaLinux:8all versions · fixed in 1.14.3-2.module_el8.6.0+2780+a40f65e1

37 more package ranges on OSV.dev

Vendor advisories

CVE-2023-27043 Red Hat Product Security1,062 products fixed · 41 known affected
python: Parsing errors in email/_parseaddr.py lead to incorrect value in email address part of tuple
python as a component of Red Hat Enterprise Linux 6 · python-devel as a component of Red Hat Enterprise Linux 6 · python-libs as a component of Red Hat Enterprise Linux 6 · +38 more
ICSA-26-134-16 CISA11 known affected
Siemens Ruggedcom Rox
RUGGEDCOM ROX MX5000 · RUGGEDCOM ROX MX5000RE · RUGGEDCOM ROX RX1400 · +8 more
SSA-577017 Siemens ProductCERT11 known affected
SSA-577017: Multiple Vulnerabilities in Ruggedcom Rox Before 2.17.1
RUGGEDCOM ROX MX5000 · RUGGEDCOM ROX MX5000RE · RUGGEDCOM ROX RX1400 · +8 more
SSA-202008 Siemens ProductCERT11 known affected
SSA-202008: Multiple Vulnerabilities in Ruggedcom Rox Before V2.17.0
RUGGEDCOM ROX MX5000 · RUGGEDCOM ROX MX5000RE · RUGGEDCOM ROX RX1400 · +8 more
RHSA-2024:3062 Red Hat Product Security57 products fixed
Red Hat Security Advisory: python3.11 security update
RHSA-2024:2985 Red Hat Product Security229 products fixed
Red Hat Security Advisory: python39:3.9 and python39-devel:3.9 security update

7 more advisories

Full record on NVD

Fix

Update Python to 3.12.6 · 3.11.10 · 3.10.15 · 3.9.20 · 3.8.20
Vendor fix CISA ICSA-26-134-16 · 11 productsUpdate to V2.17.1 or later version
Vendor fix Siemens ProductCERT SSA-577017 · 11 productsUpdate to V2.17.1 or later version
Vendor fix Siemens ProductCERT SSA-202008 · 11 productsUpdate to V2.17.0 or later version
Vendor fix Red Hat Product Security RHSA-2024:3062 · 57 productsFor details on how to apply this update, which includes the changes described in this advisory, refer to: https://access.redhat.com/articles/11258
Vendor fix Red Hat Product Security RHSA-2024:1383 · 89 productsBefore applying this update, make sure all previously released errata relevant to your system have been applied. For details on how to apply this update, refer to: https://access.redhat.com/articles/11258
No fix planned, says the vendor Red Hat Product Security CVE-2023-27043 · 23 productsOut of support scope

Advisories and patches

python.orgVendor Advisory
python-security.readthedocs.ioVendor Advisory

Detection

Nuclei template: none so far
Exploit-DB: no entry
Proof-of-concept repositories: none listed

Sources

CISA-ADPSSVC decisionpoc2025-12-17
OpenCVESSVC decisionpoc—
CISA-ADPCVSS 3.15.32025-06-03
NVDCVSS 3.15.3read 2026-10-23
CISA-ADPweakness (CWE)CWE-1286, CWE-202025-06-03
NVDweakness (CWE)CWE-20read 2026-10-23
FIRST EPSSEPSS score2.5 %2026-10-26
OSVaffected packages—

Technical details

CVSS v3 Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:N
Published: 2023-04-19
Last Modified: 2026-06-17
NVD status: Modified

Frequently asked questions

What is CVE-2023-27043?

Is CVE-2023-27043 actively exploited?

A proof-of-concept exploit exists for CVE-2023-27043, but active exploitation has not been confirmed at this time.

What is the CVSS score for CVE-2023-27043?

CVE-2023-27043 has a CVSS v3 base score of 5.3 (MEDIUM severity), with vector string CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:N.

Running Python? Hear about its next vulnerability

Surveillance reads the versions in your stack — a domain, a lockfile or a list — checks each CVE against the ranges its sources publish, and alerts you when one you run is exploited or enters CISA KEV. A version it cannot read stays « version not verified ».

Get alerts for this product CISA KEV additions, October 2026 Search CVEs

No credit card required · No monthly cap on website lookups · 250 API requests/month

Go further

Following what attackers exploit right now? The CISA KEV additions of the month, with their patch deadlines.
Running this software? Vulnerability monitoring alerts you to new vulnerabilities in your products.

Related vulnerabilities

Same product first, then the same vendor advisory and the same publication week.

Back to CVE Database