What’s Vulnerable › Vulnerabilities

CVE-2023-36632

• Severity: high (CVSS 7.5 v3.1)
• Exploited in the wild: not listed in CISA KEV
• EPSS: 1.6% probability of exploitation in the next 30 days
• Public exploit or detection template: yes
• Published: 2023-06-25 · updated 2026-06-17
• Weakness: CWE-674

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.

Affected products

• Python: through 3.11.4

References

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

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