CVE-2026-55618 eml_parser: URL extraction bypass via HTML entities in URLs
Attackers can hide malicious URLs in emails using HTML entities, bypassing security gateways that rely on eml_parser for threat detection.
- Exploited in the wild
- Not known
- Login needed
- Not needed
- Attackable
- Over the internet
- Victim action needed
- A user has to click or open something
- Fix
- Available
What is CVE-2026-55618?
CVE-2026-55618 is a medium-severity vulnerability in GOVCERT-LU eml_parser, published on 25 Aug 2026. An attacker can exploit it over the internet without logging in, and only if a user opens a file or follows a link.
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, the clean_found_uri function in eml_parser/parser.py validates potential URL strings before unescaping HTML entities used for colon, slash, or period characters. Valid encoded URLs and their host names are therefore rejected and omitted from the extracted URL and domain lists. Email security gateways and SOC pipelines that use those lists as indicators of compromise may fail to submit the hidden URLs to threat intelligence feeds, reputation services, or sandboxes, allowing malicious links to bypass inspection. This issue is fixed in version 3.0.2.
Weakness: CWE-116
Which versions are affected by CVE-2026-55618?
3 open source packages ship an affected version, including eml_parser and eml-parser.
| Package | Affected | Fixed in |
|---|---|---|
eml_parser PyPI | All versions | 3.0.2 |
eml-parser PyPI | All versions | 3.0.2 |
eml-parser PyPI | All versions | 3.0.2 |
How do I fix CVE-2026-55618?
Upgrade eml_parser to 3.0.2 or later.
Is CVE-2026-55618 being exploited?
There is no known exploitation of CVE-2026-55618 in the wild and no public exploit code.
Sources
Also known as GHSA-fxgq-9m89-cxj9, PYSEC-2026-3831.