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Vulnerability record · CVE-2023-36632 · published 25 June 2023

CVE-2023-36632: Python vulnerability

Python · Python

The legacy email.utils.parseaddr function in Python through 3.11.4 allows attackers to trigger "RecursionError: maximum recursion depth exceeded while calling a Python object" via a crafted argument. This argument is plausibly an untrusted value from an application's input data that was supposed to contain a name and an e-mail address. NOTE: email.utils.parseaddr is categorized as a Legacy API in the documentation of the Python email package. Applications should instead use the email.parser.BytesParser or email.parser.Parser class. NOTE: the vendor's perspective is that this is neither a vulnerability nor a bug. The email package is intended to have size limits and to throw an exception when limits are exceeded; they were exceeded by the example demonstration code.

7.5 CVSS 3.1 High EPSS 1.6% · top 24.0% CWE-674 · CWE-674
7.5CVSS 3.1 base score
1.6%EPSS exploitation probability, 30 days
NoNot in CISA KEV
1Affected product versions listed by NVD
8References, 2 tagged exploit
17 Jun 2026Last modified by NVD

Description

The legacy email.utils.parseaddr function in Python through 3.11.4 allows attackers to trigger "RecursionError: maximum recursion depth exceeded while calling a Python object" via a crafted argument. This argument is plausibly an untrusted value from an application's input data that was supposed to contain a name and an e-mail address. NOTE: email.utils.parseaddr is categorized as a Legacy API in the documentation of the Python email package. Applications should instead use the email.parser.BytesParser or email.parser.Parser class. NOTE: the vendor's perspective is that this is neither a vulnerability nor a bug. The email package is intended to have size limits and to throw an exception when limits are exceeded; they were exceeded by the example demonstration code.

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

Affected products

1 vulnerable configurations from NVD's CPE data, grouped by vendor and product.

References

LinkTags
https://docs.python.org/3/library/email.html Product
https://docs.python.org/3/library/email.utils.html Product
https://github.com/Daybreak2019/PoC_python3.9_Vul/blob/main/RecursionError-email.utils.parseaddr.py Product
https://github.com/python/cpython/issues/103800 ExploitIssue Tracking
https://docs.python.org/3/library/email.html Product
https://docs.python.org/3/library/email.utils.html Product
https://github.com/Daybreak2019/PoC_python3.9_Vul/blob/main/RecursionError-email.utils.parseaddr.py Product
https://github.com/python/cpython/issues/103800 ExploitIssue Tracking

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Source: NIST National Vulnerability Database (record CVE-2023-36632), CISA KEV, FIRST EPSS (scores of 2026-11-14). This page is refreshed as NVD updates the record.