eml_parser serves as a python module for parsing eml files and returning various information found in the e-mail as well as computed information. Prior to 3.0.1, EmlParser.get_raw_body_text() recurses unconditionally for every nested message/rfc822 attachment without any depth limit. An attacker who can supply a badly crafted EML file with approximately 120 nested message/rfc822 parts triggers an unhandled RecursionError and aborts parsing of the message. A 12 KB EML file is enough to crash a worker. Though this causes the parser to crash, it is an unlikely scenario as the suggested EML that crashes the parser would not pass basic RFC compliance tests. This vulnerability is fixed in 3.0.1.

Affected: PyPI: eml_parser

### Summary

`EmlParser.get_raw_body_text()` recurses unconditionally for every nested `message/rfc822` attachment without any depth limit. An attacker who can supply a badly crafted EML file with approximately 120 nested `message/rfc822` parts triggers an unhandled `RecursionError` and aborts parsing of the message. A 12 KB EML file is enough to crash a worker. Though this causes the parser to crash, it is an unlikely scenario as the suggested EML that crashes the parser would not pass basic RFC compliance tests.

### Details

The vulnerable function is `EmlParser.get_raw_body_text()` in `eml_parser/parser.py`. For every part of type `multipart/*`, the function iterates over its sub-parts; for every sub-part of type `message/rfc822`, it calls itself recursively on the inner message:

There is no depth parameter and no early-abort. CPython's default `sys.recursionlimit` is 1000. Each level of `message/rfc822` nesting adds approximately 8 frames to the stack (parser code + stdlib `_header_value_parser` calls), so roughly 120 nested levels exhaust the limit.

The `RecursionError` is not caught anywhere along the call chain, so it propagates out of `decode_email_bytes()` and aborts processing of the entire message.

### PoC

Environment: Python 3.12.3, eml_parser 3.0.0 (`pip install eml_parser==3.0.0`), default `sys.recursionlimit=1000`, Ubuntu 24.04 aarch64. No special configuration of `EmlParser`, default constructor.

Self-contained reproducer that builds the PoC and trigge…

Affected: PyPI: eml-parser

### Summary

`EmlParser.get_raw_body_text()` recurses unconditionally for every nested `message/rfc822` attachment without any depth limit. An attacker who can supply a badly crafted EML file with approximately 120 nested `message/rfc822` parts triggers an unhandled `RecursionError` and aborts parsing of the message. A 12 KB EML file is enough to crash a worker. Though this causes the parser to crash, it is an unlikely scenario as the suggested EML that crashes the parser would not pass basic RFC compliance tests.

### Details

The vulnerable function is `EmlParser.get_raw_body_text()` in `eml_parser/parser.py`. For every part of type `multipart/*`, the function iterates over its sub-parts; for every sub-part of type `message/rfc822`, it calls itself recursively on the inner message:

There is no depth parameter and no early-abort. CPython's default `sys.recursionlimit` is 1000. Each level of `message/rfc822` nesting adds approximately 8 frames to the stack (parser code + stdlib `_header_value_parser` calls), so roughly 120 nested levels exhaust the limit.

The `RecursionError` is not caught anywhere along the call chain, so it propagates out of `decode_email_bytes()` and aborts processing of the entire message.

### PoC

Environment: Python 3.12.3, eml_parser 3.0.0 (`pip install eml_parser==3.0.0`), default `sys.recursionlimit=1000`, Ubuntu 24.04 aarch64. No special configuration of `EmlParser`, default constructor.

Self-contained reproducer that builds the PoC and trigge…