eml_parser vulnerabilities

eml_parser before version 3.0.2 has a quadratic-time regex-based loop in the noparenthesis function when processing Received: headers with nested parentheses. A single header with 5000 nested parentheses causes about 1.3 seconds of CPU saturation per message, and doubling the nesting depth quadruples the running time. Attackers can submit small EML files that consume multiple seconds of processing time, causing latency and potential outages.

eml_parser before version 3.0.2 contains a stack overflow vulnerability in the header_fetch_parse function when parsing nested CFWS constructs in email headers. An attacker can send a specially crafted EML file that causes an unhandled RecursionError and aborts parsing of the entire message. This can disrupt SOC pipelines processing untrusted EML files.

eml_parser before version 3.0.2 contains a vulnerability in the clean_found_uri function that incorrectly validates URLs before unescaping HTML entities for colon, slash, or period characters. As a result, valid encoded URLs and their hostnames are rejected and omitted from extracted URL and domain lists. Email security gateways and SOC pipelines using these lists as indicators of compromise may fail to submit hidden URLs to threat intelligence feeds, reputation services, or sandboxes, allowing malicious links to bypass inspection.

In eml_parser before version 3.0.1, the EmlParser.get_raw_body_text() function recursively processes nested message/rfc822 attachments without any depth limit. An attacker can supply a crafted EML file with approximately 120 nested parts, causing an unhandled RecursionError and aborting parsing.