CVE-2023-36632

Name: CVE-2023-36632
Creator: NVD / NIST
Published: 2023-06-25T18:15:09.313+00:00
License: https://creativecommons.org/publicdomain/zero/1.0/

HIGHCVSS 7.5/10EPSS 1.32%

Last modified Jun 17, 2026

CVE-2023-36632 is a high-severity vulnerability rated 7.5/10 on the CVSS scale. 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. EPSS estimates a 1.32% chance of exploitation in the next 30 days.

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.

Metrics

CVSS 3.1

7.5/10

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

EPSS Probability

1.32%

67.2th percentile

Probability of exploitation in the next 30 days. Learn more

Weakness Enumeration

CWE-674

Affected Software

Vendor	Product	Versions
Python	Python	<= 3.11.4

References

https://docs.python.org/3/library/email.htmlProduct
https://docs.python.org/3/library/email.utils.htmlProduct
https://github.com/Daybreak2019/PoC_python3.9_Vul/blob/main/RecursionError-email.utils.parseaddr.pyProduct
https://github.com/python/cpython/issues/103800Exploit, Issue Tracking
https://docs.python.org/3/library/email.htmlProduct
https://docs.python.org/3/library/email.utils.htmlProduct
https://github.com/Daybreak2019/PoC_python3.9_Vul/blob/main/RecursionError-email.utils.parseaddr.pyProduct
https://github.com/python/cpython/issues/103800Exploit, Issue Tracking

Timeline

Published: Jun 25, 2023
Last Modified: Jun 17, 2026
Status: Modified

Frequently Asked Questions

What is CVE-2023-36632?

How severe is CVE-2023-36632?

CVE-2023-36632 has a CVSS score of 7.5/10 (HIGH severity). The EPSS model estimates a 1.32% probability of exploitation in the next 30 days.

How do I fix CVE-2023-36632?

Check the vendor references and advisories linked above for patched versions and mitigation guidance. You can also run a Strix scan to test if your systems are affected.

Are you affected by CVE-2023-36632?

Run a free Strix scan to check your systems for this vulnerability.

Scan your code now

Source: NVD / NIST