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Vulnerability · Published Aug 25, 2026 · Assigned by GitHub_M

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

Medium 5.3

In plain English

A medium-severity resource allocation without limits in eml_parser from GOVCERT-LU. There are no confirmed reports of exploitation so far. The chance it is exploited in the next 30 days is estimated at 0.5% (higher than 45% of all known vulnerabilities). Fixed versions are available - upgrade the affected package.

Severity (CVSS 3.1)5.3Medium
Exploit odds (30 days)0.5%top 55.4% of all CVEs
Exploited in the wildNo reportsCISA SSVC: none
Attack toolingNoneno public tooling known

Official 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 packages & fixed versions

EcosystemPackageFixed inAdvisory
PyPIeml-parser3.0.2GHSA-m66c-fw79-6359
PyPIeml-parser3.0.2PYSEC-2026-3833

Affected products (as reported)

VendorProductVersions
GOVCERT-LU eml_parser < 3.0.2

Weakness: CWE-770, CWE-1124 · Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L

References