GitHub Advisoryadvisory · PyPI
GHSA-fxgq-9m89-cxj9 eml_parser has a URL extraction bypass via HTML entities in URLs
MEDIUM
Official page ↗
- Aliases
- CVE-2026-55618
- Ecosystem
- PyPI
- Packages
- eml_parser
- Severity
- Moderate
- CVSS vector
- CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:H/A:N
- Weaknesses
- CWE-116
- Reviewed
- 2026-08-25
Affected packages
• PyPI eml_parser: < 3.0.2 → fixed in 3.0.2
Description
Summary
`eml_parser` performs certain validations on potential URL strings to discard bogus values. In versions prior to `3.0.2`, this validation was performed before unescaping any HTML entities that might occur in the string. This caused the library to wrongfully reject valid URLs that use HTML entities for the `:`, `/`, or `.` characters. These URLs would then not be included in the list of extracted URLs. Similarly, the host parts of such URLs would not be extracted.
For example, neither the URL `https://phishing.example.com` nor its host (`phishing.example.com`) would appear in the parsing result.
Impact
`eml_parser` is used in email security gateways and SOC pipelines to extract URLs as IOCs. Those URLs are then checked against threat-intel feeds, URL reputation services, and sandboxes. A URL that is not extracted is never checked.
Patches
Since version 3.0.2 the library unescapes all HTML entities in every URL before deciding to accept or reject it. A test was added to prevent regressions.
Related
Alias · CVE (1)
- CVE-2026-55618 eml_parser serves as a python module for parsing eml files and returning various information found in the e-mail as well as computed… vulnerability
Weakness · CWE (1)
- CWE-116 Improper Encoding or Escaping of Output weakness
References
- https://github.com/GOVCERT-LU/eml_parser/security/advisories/GHSA-fxgq-9m89-cxj9 web
- https://github.com/GOVCERT-LU/eml_parser/pull/90 web
- https://github.com/GOVCERT-LU/eml_parser/commit/746a69f86443eb0b6a47f77db3cfe727c21f92b3 web
- https://github.com/GOVCERT-LU/eml_parser package
- https://github.com/GOVCERT-LU/eml_parser/releases/tag/v3.0.2 web