What’s Vulnerable › Vulnerabilities

CVE-2026-55619: eml_parser: Parser DoS via deeply nested parentheses in e-mail headers

• Severity: medium (CVSS 5.3 v3.1)
• Exploited in the wild: not listed in CISA KEV
• EPSS: 0.5% probability of exploitation in the next 30 days
• Public exploit or detection template: none known
• Published: 2026-08-25 · updated 2026-09-09
• Weakness: CWE-770

Description

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 3.0.2, eml_parser.parser.HeaderParser.header_fetch_parse in eml_parser/parser.py uses email.utils.getaddresses() to parse address-bearing e-mail headers. A deeply nested CFWS comment construct exhausts the standard-library recursive descent parser's call stack and raises RecursionError, which is not caught and therefore aborts parsing of the entire message. An attacker can disrupt SOC pipelines that process untrusted EML files, although callers already need to handle exceptions from malformed or pathological messages. This issue is fixed in version 3.0.2.

Affected products

• GOVCERT-LU eml_parser: before 3.0.2

References

• https://github.com/GOVCERT-LU/eml_parser/commit/746a69f86443eb0b6a47f77db3cfe727c21f92b3
• https://github.com/GOVCERT-LU/eml_parser/pull/90
• https://github.com/GOVCERT-LU/eml_parser/releases/tag/v3.0.2
• https://github.com/GOVCERT-LU/eml_parser/security/advisories/GHSA-m66c-fw79-6359

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