CVE-2026-55618: GOVCERT-LU eml_parser URL extraction bypass via HTML entities

CVE-2026-55618 · Severity: medium · CVSS 6.5 · Published 2026-08-25

eml_parser is a library used by email security systems and security operations centers to extract URLs from email messages for threat analysis. The vulnerability allows attackers to craft emails with URLs that use HTML entity encoding (e.g., `https://phishing.com`) to evade detection, causing malicious URLs to be missed by security scanning systems that rely on this library.

Technologies: GOVCERT-LU Eml Parser, eml-parser (PyPI). Vendors: GOVCERT-LU, PyPI.

Quick answers

Is CVE-2026-55618 exploited in the wild?
No. Junglewise Threat Intelligence has no report of CVE-2026-55618 being exploited in the wild.
How severe is CVE-2026-55618?
Medium severity, with a CVSS score of 6.5, published 25 August 2026.
Which products and versions are affected?
GOVCERT-LU Eml Parser < 3.0.2; eml-parser (PyPI) ECOSYSTEM:introduced=0,fixed=3.0.2.
Is there a fix for CVE-2026-55618?
Yes. eml-parser (PyPI): upgrade to 3.0.2 or later. Junglewise finds every place you run it, drafts the upgrade and applies it once you approve.
How is CVE-2026-55618 attacked?
It is attacked over the network, in a software library.
Am I affected by CVE-2026-55618?
Check whether you run GOVCERT-LU Eml Parser or eml-parser (PyPI) at an affected version. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.

How to fix

  • eml-parser (PyPI): upgrade to 3.0.2 or later
    pip install "eml-parser>=3.0.2"

Technical details

The vulnerability is a validation bypass caused by improper encoding/escaping (CWE-116). eml_parser validates URL strings to filter out bogus values, but this validation occurs before HTML entity decoding. URLs using HTML entity encoding for critical characters (`:`, `/`, `.`) are incorrectly rejected, preventing both the URL and its host from appearing in the extraction results. For example, `https&#58;&#47;&#47;phishing&#46;example&#46;com` decodes to `https://phishing.example.com` but is rejected before decoding. The fix in version 3.0.2 unescape HTML entities before validation. The attack requires user interaction (opening an email) but no authentication or special privileges, and can be delivered across the network via standard email protocols.

Affected products

  • GOVCERT-LU eml_parser < 3.0.2

Identifiers

  • CVE-2026-55618
  • GHSA-fxgq-9m89-cxj9
  • PYSEC-2026-3831

Timeline

  • 2026-06-15: disclosed: Published to GitHub Advisory Database
  • 2026-08-25: patched: Version 3.0.2 released with fix

References

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