# eml_parser has a URL extraction bypass via HTML entities in URLs

Advisory record · `GHSA-fxgq-9m89-cxj9`

- **Identifiers:** `GHSA-fxgq-9m89-cxj9` · `CVE-2026-55618` · `PYSEC-2026-3831`
- **State:** Confirmed
- **Severity:** CVSS 6.5 Medium
- **Critical:** No
- **Weakness (CWE):** [CWE-116](https://cwe.mitre.org/data/definitions/116.html)
- **Tags:** [CWE-116](https://agentprime.io/advisories/tag/cwe-116.md)
- **Published:** 25 Aug 2026
- **Updated:** 10 Sept 2026
- **Reviewed by a person:** No

Published by the GitHub Advisory Database at 25 Aug 2026, 18:23 UTC. agentprime has not analysed this yet, so whether it affects any app is not known.

## Affected packages

- `eml-parser` (PyPI): affected `<3.0.2`; fixed in `3.0.2`

## Machine-written summary

Summary written by Claude Haiku from the source advisory. Not reviewed by a person.

> eml_parser versions before 3.0.2 wrongly reject valid URLs that encode the characters ':', '/', or '.' as HTML entities, so those URLs and their host names are left out of the extracted results. An attacker who sends a crafted email can therefore hide malicious links from tools that rely on eml_parser's URL list, such as threat-intel checks and sandboxes. Upgrade to eml_parser 3.0.2 or later, which unescapes HTML entities before validating URLs.

Written 1 Nov 2026.

## Not analysed yet

We haven’t published our analysis of this Advisory yet. Once a person has reviewed it, this page will say what’s vulnerable, what has to be true for your app to be affected, and how to check.

## Severity and exploitation

- 6.5 Medium, CVSS 3.1: `CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:H/A:N`, from CNA (GitHub_M)

- **CISA KEV:** Not listed.
- **EPSS:** 0.0052, the 44th percentile, on 5 Nov 2026: FIRST’s estimate of the chance of exploitation in the next 30 days.

## Timeline

- 31 Oct 2026, 14:10 UTC: First seen by agentprime
- 31 Oct 2026, 14:10 UTC: [Confirmed by OSV](https://osv.dev/vulnerability/GHSA-fxgq-9m89-cxj9)

## Sources

- [GitHub Advisory Database: GHSA-fxgq-9m89-cxj9](https://github.com/advisories/GHSA-fxgq-9m89-cxj9)
- [OSV: GHSA-fxgq-9m89-cxj9](https://osv.dev/vulnerability/GHSA-fxgq-9m89-cxj9)
- <https://github.com/GOVCERT-LU/eml_parser/security/advisories/GHSA-fxgq-9m89-cxj9>
- <https://github.com/GOVCERT-LU/eml_parser/pull/90>
- <https://github.com/GOVCERT-LU/eml_parser/commit/746a69f86443eb0b6a47f77db3cfe727c21f92b3>
- <https://github.com/GOVCERT-LU/eml_parser>
- <https://github.com/GOVCERT-LU/eml_parser/releases/tag/v3.0.2>

Facts on this page come from the GitHub Advisory Database (CC-BY 4.0), OSV and the other sources listed, as published. We don’t reproduce full advisory descriptions, which can contain exploit code.

## Check whether this affects you

A Match means an installed version is in the affected range above. Most don’t affect the app; agentprime hasn’t analysed this one yet.

- With the agentprime MCP server (<https://api.agentprime.io/mcp>), ask your agent to check the project: `check_lockfile` sends a lockfile, `check_packages` a list of installed packages, and both return the Matches and the upgrades that clear them. `get_advisory` returns this record. Setup: <https://agentprime.io/mcp.md>
- In a browser: <https://agentprime.io/check/> reads your lockfile in the browser, never uploading it.
- Whether it touches your code, with file and line: the Claude Code plugin, <https://agentprime.io/plugin.md>
- As JSON: <https://api.agentprime.io/v1/advisories/GHSA-fxgq-9m89-cxj9>, or `POST https://api.agentprime.io/v1/match` with your packages (<https://agentprime.io/api.md>)

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The web page: <https://agentprime.io/advisories/GHSA-fxgq-9m89-cxj9/>. Everything for agents: <https://agentprime.io/llms.txt>.