# Reverse Tabnabbing in showdown

Advisory record · `GHSA-h6mq-3cj6-h738`

- **Identifiers:** `GHSA-h6mq-3cj6-h738`
- **State:** Confirmed
- **Severity:** CVSS 3.1 Low
- **Critical:** No
- **Weakness (CWE):** [CWE-1022](https://cwe.mitre.org/data/definitions/1022.html)
- **Tags:** [CWE-1022](https://agentprime.io/advisories/tag/cwe-1022.md)
- **Published:** 3 Sept 2020
- **Updated:** 1 Oct 2021
- **Reviewed by a person:** No

Published by the GitHub Advisory Database at 3 Sept 2020, 23:21 UTC. agentprime has not analysed this yet, so whether it affects any app is not known.

## Affected packages

- `showdown` (npm): affected `<1.9.1`; fixed in `1.9.1`

## 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

- 3.1 Low, CVSS 3.1: `CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:U/C:L/I:N/A:N`, from GitHub Advisory Database

- **CISA KEV:** Not listed.
- **EPSS:** No score.

## Timeline

This record came from the full history of the GitHub Advisory Database, published 3 Sept 2020. New records show when each source confirmed them.

## Sources

- [GitHub Advisory Database: GHSA-h6mq-3cj6-h738](https://github.com/advisories/GHSA-h6mq-3cj6-h738)
- [OSV: GHSA-h6mq-3cj6-h738](https://osv.dev/vulnerability/GHSA-h6mq-3cj6-h738)
- <https://github.com/showdownjs/showdown/pull/670>
- <https://github.com/showdownjs/showdown/commit/1cd281f0643ef613dc1d36847d4c6cbb22501d91>
- <https://github.com/showdownjs/showdown>
- <https://snyk.io/vuln/SNYK-JS-SHOWDOWN-469487>
- <https://www.npmjs.com/advisories/1302>

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-h6mq-3cj6-h738>, 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-h6mq-3cj6-h738/>. Everything for agents: <https://agentprime.io/llms.txt>.