CVE-2023-36632
The legacy email.utils.parseaddr function in Python through 3.11.4 allows attackers to trigger "RecursionError: maximum recursion depth…
- 7.5HighCVSS base score
- 1.6%Exploitation in 30 daysEPSS · top 24% of all CVEs
- NoKnown exploitednot in CISA's KEV catalog
- YesPublic exploitsa reference or SSVC says so
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.
Public exploit
An exploit or proof of concept is public: anyone can try it against an unpatched system. CISA's SSVC rates its exploitation: a proof of concept is public.
Timeline
Published
- 17 months later
· 17 months later
Record updated
Changes after publication (a new score, a public exploit, EPSS crossing 1, 10 or 50 %, leaving KEV) are kept since November 2026; earlier ones are not known.
Scores
| Scored by | CVSS | Score | Vector |
|---|---|---|---|
| NVDNVD · Modified | 3.1 | High7.5 | CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H |
- EPSS (exploitation in 30 days)
- 1.6% · top 24% of all CVEs (11 Nov 2026)
- CISA SSVC
- Exploitation: poc · Automatable: yes · Technical impact: partial
The list uses the assigner's score when there is one, then CISA's, then NVD's: High 7.5.
Affected products
n/a
- affected n/a
References
References4
- https://docs.python.org/3/library/email.utils.html (opens in a new tab)x_transferred
- https://docs.python.org/3/library/email.html (opens in a new tab)x_transferred
- https://github.com/Daybreak2019/PoC_python3.9_Vul/blob/main/RecursionError-email.utils.parseaddr.py (opens in a new tab)x_transferred
- https://github.com/python/cpython/issues/103800 (opens in a new tab)x_transferred
Sources
The same CVE in the primary databases and aggregators, to check against.
- CVE.org record (opens in a new tab)
- CVE List JSON (GitHub) (opens in a new tab)
- NVD (opens in a new tab)
- FIRST EPSS (opens in a new tab)
- EUVD EUVD-2023-40576 (opens in a new tab)
- OSV.dev (opens in a new tab)
- GitHub Advisories (opens in a new tab)
- CIRCL Vulnerability-Lookup (opens in a new tab)
Badge for a README or a ticket
[](https://cveledger.app/cve/CVE-2023-36632)Record last updated .